ZOLEO ZL1500 vs Bivy Stick: screenless Iridium communicators for phone users
Compare two screenless Iridium communicators that rely on a paired phone for typed messages and send SOS alerts to Global Rescue, by plan structure, pause terms, battery claims and stated build figures.
The decision in brief
How the options differ
Both exact US packages need an active plan, carry a dedicated number and use device buttons for check-in and SOS while the app handles typed messages. They differ in how the plan meters use, what happens when you stop using the device, how the battery figure is stated and how consistently the manufacturer documents weight and water protection.
By CompareFoundry · Published · Editorial review · Manufacturer documentation, not hands-on testing.
The buying guide
Package and specification details
Compare how each plan counts use
ZOLEO offers two monthly plans with a three-month minimum term: Prepare, whose satellite message allowance also counts check-ins, and Protect, with unlimited satellite messages under a Fair Use Policy. Bivy plans are credit-based in Basic, Plus or Unlimited tiers, billed monthly or annually, with free check-ins and tracking that uses credits. Both state that SOS messages do not count against the plan.
Sources · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Check what happens when you stop using it
After its initial term, ZOLEO lets you pause service and keep the number and email, but states the device cannot send messages, check-ins or SOS alerts while paused. Bivy's plans page describes changing or deactivating a plan instead, and deactivating loses rollover credits and the assigned number.
Sources · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Read the battery and build figures with their conditions
ZOLEO states over 200 hours of battery life without naming an interval, 150 g and IP68 to 1.5 m for 30 minutes. ACR states up to 120 hours with mailbox checks every 15 minutes, but its product page and user guide disagree on weight (112 g or 95 g) and water rating (IP66 or IPX7).
Can either device send a typed message without a phone?
Neither manufacturer describes that. ZOLEO's device on its own sends a check-in or an SOS, and the Bivy Stick's buttons send a preset check-in, start tracking or trigger SOS; typed messages are written in each maker's app.
These manufacturer specifications do not establish measured performance, noise, long-term reliability or running cost. We have not independently tested these products. Check current prices, stock and operating-space instructions with the seller and manufacturer.
Bivy Go supplies a device with a 6- or 12-month Unlimited plan and is a different offer; the Bivy Stick MESH is a different product. Mount kits and the solar panel are optional accessories.
A data plan and its activation fee are separate purchases. Price and availability are not recorded.
The link may open several packages. Check current price and availability with the seller. Opens in a new tab.
Satellite network and coverage claim
The satellite network the device uses and the coverage the manufacturer claims for it, including any cellular or Wi-Fi fallback through a paired phone.
Coverage is a manufacturer claim, not a tested result. Terrain, tree cover and buildings block satellites, and some countries restrict satellite communicators.
Satellite Communicator ZL1500 Limestone (US)Iridium satellite network, which ZOLEO describes as the only commercial satellite network with truly global coverage. Paired with the app, messaging also moves over cellular and Wi-Fi when available.ZOLEO states satellite communication requires a clear view of the sky, connectivity is not guaranteed and coverage details apply, and travelers should check local restrictions.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Iridium satellite network; ACR describes 100% global coverage, and the user guide states all Bivy plans use the Iridium network.Coverage is a manufacturer claim. ACR lists countries it knows prohibit satellite communicators and makes compliance the user's responsibility.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
SOS coordination service
How an SOS is triggered and the emergency response coordination service the manufacturer names to receive it.
The named service contacts responders on your behalf. It does not guarantee rescue or a response time, and rescue costs can be the user's responsibility.
Satellite Communicator ZL1500 Limestone (US)Covered SOS button on the device, or SOS in the ZOLEO app. Alerts go to Global Rescue, which ZOLEO names as its emergency response coordination partner, monitored 24/7/365 with two-way progress updates in the app.ZOLEO states the ZL1500 sends an alert on a single press, location updates every six minutes during an alert, and SOS messages are included in all plans without counting toward the allowance. ZOLEO states it is not a licensed emergency dispatch service and does not guarantee rescue or response. Medical Assist is a separate non-emergency service, and a Global Rescue Field Rescue Membership is an optional add-on.Sources · 2026-10-21ZOLEO: How SOS works on ZOLEO (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Dedicated SOS button under a red flap, or SOS in the Bivy app, with 24/7 SOS monitoring by Global Rescue and two-way texting with Global Rescue through the app.ACR states SOS messages are included and do not decrement plan credits, and the guide states location is sent once per minute for 10 minutes, then every 10 minutes. ACR states the user could be responsible for rescue costs; a Global Rescue membership is optional. Dispatch of search and rescue is the manufacturer's description, not a guarantee.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Plan structure
The named service plans, billing period, minimum term, activation requirement and add-ons the manufacturer documents. Prices are not recorded.
Plan terms change. Check the minimum term, auto-renewal, cancellation terms and what each tier includes on the plans page before activating.
Satellite Communicator ZL1500 Limestone (US)Active monthly plan required: Prepare (a monthly satellite message allowance) or Protect (unlimited satellite messages under a Fair Use Policy). Three-month minimum term and a one-time activation fee, then month-to-month auto-renewal. Location Share+ is an optional add-on.ZOLEO's US plans page states that cancelling during the initial term carries an early cancellation fee for the remaining term, check-ins count toward the Prepare allowance, cancelling loses the SMS number, email and history, and cellular or Wi-Fi data costs are the user's. Prices are not recorded.Source · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Active Bivy base data plan required, chosen in the Bivy app at activation: Basic, Plus or Unlimited, monthly or annual (one-year contract). Credit-based: messages, weather and tracking use credits; check-ins are free. An initial commitment period and a one-time activation fee apply.The US plans page states a one-time 3-month commitment on Plus or Unlimited, Basic only after the initiation period, monthly auto-renewal afterwards, rollover of unused Basic and Plus credits, and loss of credits and number on deactivation. The user guide instead states a four-month commitment for the first activation. Prices are not recorded.Sources · 2026-10-21ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Active plan required for messaging and SOS
Whether the manufacturer states that messaging and SOS need an active service subscription.
A device bought without a plan cannot message or send an SOS over satellite. The plan is a separate purchase with its own activation.
Satellite Communicator ZL1500 Limestone (US)YesZOLEO: "Active subscription required." The SOS page states an active ZOLEO subscription plan is required before using SOS or other connected features.Sources · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: How SOS works on ZOLEO (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)YesThe user guide: "Messaging, tracking, SOS, weather and all Bivy Stick features require an active Bivy Stick base data plan." The product page states a monthly subscription is required.Sources · 2026-10-21ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Service can be paused or suspended
Whether the manufacturer documents pausing or suspending service without cancelling the account.
Read the note: some pauses carry a charge or a time limit, and SOS may be unavailable while service is paused.
Satellite Communicator ZL1500 Limestone (US)YesAfter the initial 3-month term, service can be paused for a monthly charge while keeping the SMS number and email. ZOLEO states that while paused the device cannot send messages, check-ins or SOS alerts.Source · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Not verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
The plans page describes changing or deactivating a plan after the initial commitment, with loss of rollover credits and the assigned number on deactivation; it does not describe a pause that keeps the account.Source · 2026-10-21ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
How messages are written and read
Whether messages are composed on the device's own screen and keyboard or in a paired phone app, and which message types are documented.
Photo and voice messages, group chats and contact sync often depend on the phone app. Check which features need the phone to be working.
Satellite Communicator ZL1500 Limestone (US)No display: LEDs for messages, SOS, check-in and power. Text/SMS, email and app-to-app messages are composed in the ZOLEO app on a phone or tablet paired over Bluetooth LE (one connection at a time, range up to 50 m).Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)No display: status LEDs and buttons for power, check-in or tracking, and SOS. Messages to phone numbers, email addresses and other Bivy Sticks are typed in the Bivy app (iOS or Android) over Bluetooth LE; GroupTrack group messaging is listed on the Plus and Unlimited plans.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Custom messages without a phone
Whether the device itself can compose and read custom text messages when no phone is paired.
Screenless devices can still send a preset check-in or an SOS from their buttons; this field covers typed messages only.
Satellite Communicator ZL1500 Limestone (US)NoZOLEO describes the device on its own as sending a check-in or triggering an SOS with a button press; custom messages are written in the paired app. The device has LEDs and no screen.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)NoACR states the Bivy Stick transforms a smartphone into a satellite communicator; the device's own buttons send a preset check-in, start tracking or trigger SOS, and custom messages are written in the app.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Stated message length
The maximum length of a satellite text message published by the manufacturer.
Lengths can differ between satellite, app-to-app and SMS routes. Not stated is not the same as short.
Whether the plan assigns the device its own phone number or SMS number so others can message it first.
A dedicated number is usually lost when the plan is cancelled. Unknown means the sources read do not state one.
Satellite Communicator ZL1500 Limestone (US)YesEach plan includes a dedicated ZOLEO SMS number and email address assigned to the device; both are lost on cancellation but kept during a pause.Sources · 2026-10-21ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)YesDedicated phone number and email; the number is lost on deactivation, and a new one is assigned on reactivation.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Tracking intervals
The location-tracking send intervals the manufacturer lists and any plan or add-on that limits them.
Shorter intervals use more battery and, on some plans, more credits or messages. Some tracking needs an add-on subscription.
Satellite Communicator ZL1500 Limestone (US)Location can be shared in messages and check-ins and through a ShareMap link. Automatic breadcrumb sharing at intervals from every 6 minutes to 4 hours needs the optional Location Share+ add-on subscription.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Monthly Plans (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)2, 5, 10 (default), 30 or 60 minutes, each using plan credits at a stated rate from 1 credit per 12 minutes at the 2-minute interval to 1 credit per 6 hours at 60 minutes. Started from the app or by holding the device's check-in button.Sources · 2026-10-21ACR Electronics: Bivy Stick data plansChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Battery life at a 10-minute interval
The manufacturer's battery-life estimate when a location or message is sent every 10 minutes, with the mode and conditions in the note.
Only figures stated for a 10-minute interval are recorded here. They assume a clear sky view and are estimates, not measurements.
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
ZOLEO states over 200 hours of battery life for the ZL1500 without naming a tracking or message-check interval; no 10-minute tracking figure is published on the US pages read.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Not verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
ACR's FAQ states approximately 100 hours with 24/7 tracking without naming the interval. The default tracking interval is 10 minutes, but the figure is not attributed to it here.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Battery claims and their conditions
Every battery-life figure the manufacturer publishes, each with the interval, mode or condition it states.
A figure without a stated interval cannot be compared with one measured at a stated interval. Cold, obstructions and frequent messages shorten battery life.
Satellite Communicator ZL1500 Limestone (US)Over 200 hours of battery life; the US ZL1500 pages do not state the message-check or tracking interval behind the figure.An unrendered legacy specification block in the store page source, which also lists a Micro-USB connector unlike the USB-C ZL1500, says 200+ hours checking messages every 12 minutes; it is not attributed to the ZL1500 here.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Up to 120 hours with mailbox checks every 15 minutes, approximately 100 hours with 24/7 tracking (interval not stated) and a 2-hour SOS reserve, per the product page and its FAQ.The user guide states up to 120 hours of standard operation at the default setting.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Battery and charging
The documented battery type and capacity, charging connector and any charging limits.
Internal batteries are not user-replaceable. Bring the right cable and a power source for longer trips.
Satellite Communicator ZL1500 Limestone (US)Rechargeable battery charged over USB-C; capacity not stated on the US pages. Battery charging temperature 0 to 45 °C.Source · 2026-10-21ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)1400 mAh lithium-ion polymer battery, internal and not user-replaceable; USB-C. Charge time 2 to 4 hours, about 1.5 hours with a USB-C charger and USB-C to USB-C cable.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Device weight
The published weight of the device itself.
Where two official sources publish different weights the value is left unresolved and both are shown.
The sources give different answers, so we have not chosen one as fact. Read the attached notes and confirm the current specification before relying on it.
The product page specification table and the user guide publish different weights and dimensions. A 0.50 lb weight in the page's additional-information table is not used as the device weight.Sources · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
Water and dust rating
The IP rating and any ruggedness standard the manufacturer states, with its stated depth and duration.
Ratings are manufacturer statements about test conditions. Satellite signals do not reach a device underwater.
Satellite Communicator ZL1500 Limestone (US)IP68: dust- and water-resistant to 1.5 m (4.9 ft) for 30 minutes; shock-resistant to MIL-STD 810G.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Sources disagree
The sources give different answers, so we have not chosen one as fact. Read the attached notes and confirm the current specification before relying on it.
The operating temperature range the manufacturer publishes.
Cold reduces battery life, and charging ranges are often narrower than operating ranges.
Satellite Communicator ZL1500 Limestone (US)-20 to 55 °C (-4 to 131 °F); storage -20 to 60 °C.Source · 2026-10-21ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)Optimal operating temperature 10 to 105 °F, per the user guide.The product page does not list an operating temperature range.Source · 2026-10-21ACR Electronics: Bivy Stick User GuideChecked 2026-10-21. Read the original source and its check date before relying on this value.
In the box
Items the manufacturer or seller lists in the exact US package.
No package here includes a service plan. Mounts, cases and chargers are included only when listed.
Satellite Communicator ZL1500 Limestone (US)ZOLEO Satellite Communicator device, lanyard, carabiner, 50 cm (20 in) USB-C cable and Quick Start Guide; ZOLEO also lists its limited lifetime device warranty under What's In the Box.Sources · 2026-10-21ZOLEO: ZOLEO Satellite Communicator US store pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ZOLEO: ZOLEO Satellite Communicator overview and tech specs (US)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Bivy Stick 4601 (US)USB-C charging cable, carabiner, cord and 1/4-20 mount adaptor, per the specification table; the features list names a USB-C charging cable, carabiner, lanyard, Quick Start guide and GoPro adapter.The two lists on the same page name the cord or lanyard and the mount adaptor differently and only one mentions the Quick Start guide.Source · 2026-10-21ACR Electronics: Bivy Stick satellite communicator product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Questions to check before buying
Satellite Communicator ZL1500 Limestone (US)
The battery figure has no stated interval for this model, so it cannot be compared with the 10-minute tracking figures of other devices.
The ZL1500 succeeds the slate grey ZL1000; a legacy specification block in the US page source does not match the ZL1500 connector and is not used.
Bivy Stick 4601 (US)
Weight and water rating differ between the current product page and the 2023 user guide; confirm with ACR for the unit you buy.
The first-activation commitment differs between the plans page (3 months) and the user guide (four months), and the 120-hour battery figure is not a 10-minute tracking figure.
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