Compare two empty 40 Gb/s NVMe enclosures by bridge design, drive fit, cooling and included cables.
The decision in brief
How the options differ
Both list a 40 Gb/s host link for an empty M.2 NVMe enclosure. ACASIS pairs a JHL7440 controller with an RTL9210B chip and has no fan on this version; UGREEN uses an ASM2464PD bridge with a PWM fan. Their supported lengths, capacity limits and cables differ.
By CompareFoundry · Published · Editorial review · Manufacturer documentation, not hands-on testing.
The buying guide
Package and specification details
Bridge design and older hosts
ACASIS attributes backward compatibility with Thunderbolt 5/4/3 and USB 3.2 and older to its JHL7440 plus RTL9210B design. UGREEN lists USB4/3.2/3.1/3.0/2.0 and Thunderbolt 3/4 compatibility for its ASM2464PD bridge. Neither page states the rate on an older USB host, and neither nominal rate is a benchmark.
UGREEN lists 2230, 2242, 2260 and 2280 M/B+M-key NVMe drives up to 4TB and excludes SATA NGFF and mSATA drives. The ACASIS manual lists 2280 only, although its product page says any size, and TBU405M1 supports up to 8TB. Confirm a shorter drive with ACASIS first.
TBU405M1 is the fanless tool-free version with an aluminum shell and thermal pad; the fan model, TBU405Pro, is a different selection. UGREEN adds a PWM fan to its aluminum shell and thermal pad and includes a screwdriver and a silicone case. A fan or heat sink does not prove sustained speed for every drive.
The ACASIS manual lists one Thunderbolt cable. UGREEN lists a USB-C to USB-C cable and a USB-C to USB-A cable. Neither states cable lengths or ratings, and a cable that fits is not proof of the 40 Gb/s rate. Neither package includes an SSD.
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.
Empty enclosure only; supply a compatible SSD separately. The store shows a US delivery estimate and says it ships to 74 countries. No current stock, delivery or checkout test is claimed.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)SKU 15976, 40Gbps M.2 NVMe Enclosure with Cooling Fan, gray; enclosure only, no SSD; not the 10Gbps M.2 NVMe SATA enclosure or a Thunderbolt 5 model.
Empty enclosure only; supply a compatible SSD separately. The store says orders ship from its US warehouses. No current stock or checkout test is claimed.
The link may open several packages. Check current price and availability with the seller. Opens in a new tab.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)
Select: SKU 15976, 40Gbps M.2 NVMe Enclosure with Cooling Fan, gray; enclosure only, no SSD; not the 10Gbps M.2 NVMe SATA enclosure or a Thunderbolt 5 model.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)NoUGREEN states it does not support SATA NGFF or mSATA solid-state drives.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Supported M.2 lengths
Documented length codes and any source disagreement.
Check both the mounting position and component clearance, especially for double-sided drives.
TBU405M1 40Gbps NVMe enclosure (US selection)The manual lists 2280 (22 × 80) only; the product page says any size of PCIe NVMe SSD.Confirm mounting for a shorter drive with ACASIS before relying on it.Sources · 2026-10-21ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.ACASIS: 40Gbps Tool-free M.2 NVMe SSD Enclosure (TBU405 family) product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Storage drives supplied with the exact purchase option.
These selections are empty enclosures. A populated bundle is a different package.
TBU405M1 40Gbps NVMe enclosure (US selection)0 drivesSource · 2026-10-21ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)0 drivesThe included-components list names no SSD. A 'Hard Disk Size: 4 TB' specification attribute is not treated as a supplied drive.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Drive installation
The documented enclosure opening and drive-retention method.
Tool-free does not eliminate thermal-pad placement or careful handling of the SSD.
TBU405M1 40Gbps NVMe enclosure (US selection)Tool-free: open the bottom plate, fit the rubber stopper to hold the SSD, then close the lower cover. No driver or external power supply is required.Sources · 2026-10-21ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.ACASIS: 40Gbps Tool-free M.2 NVMe SSD Enclosure (TBU405 family) product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)A screwdriver is included; the retrieved text does not describe the drive-retention steps.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Cooling arrangement
Documented enclosure materials and heat-transfer components.
A heat sink is not proof of sustained speed or that every drive avoids throttling.
TBU405M1 40Gbps NVMe enclosure (US selection)Aluminum alloy shell with a corrugated surface and a thermal pad; no fan on TBU405M1. The built-in fan is the TBU405Pro difference.Sources · 2026-10-21ACASIS: 40Gbps Tool-free M.2 NVMe SSD Enclosure (TBU405 family) product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)Aluminum alloy shell, silicone thermal pad and a PWM fan that adjusts its speed automatically; an external silicone case is supplied.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Included host cables
Cable contents established for the selected package.
A cable that fits physically may not support the advertised rate. Regional packing lists remain separate.
TBU405M1 40Gbps NVMe enclosure (US selection)One Thunderbolt cable is listed in the manual's package contents; its length and rating are not stated.Source · 2026-10-21ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)One USB-C to USB-C cable and one USB-C to USB-A cable; lengths and rated speeds are not stated.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Host requirements
Required interface and operating conditions.
Using a faster host port does not upgrade the enclosure bridge. Formatting and file-system support are separate.
TBU405M1 40Gbps NVMe enclosure (US selection)Thunderbolt 3/4 or USB4 host for the 40 Gb/s mode. The page attributes backward compatibility with Thunderbolt 5/4/3 and USB4/3.2/3.1/3.0/2.0 to its dual-chip design but does not state the transfer rate on a USB 3.2 or older host. An iPhone 15 Pro Max may need a 10Gbps cable or a powered dock.Sources · 2026-10-21ACASIS: 40Gbps Tool-free M.2 NVMe SSD Enclosure (TBU405 family) product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)USB4-compatible Type-C interface, listed as compatible with USB4/3.2/3.1/3.0/2.0 and Thunderbolt 3/4. The 40 Gb/s rate needs a matching host and cable; the page does not state the rate through the USB-C to USB-A cable.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Explicit compatibility limits
Important exclusions and capacity or revision conditions.
Use the exact drive and enclosure revision. Do not treat a generic NVMe label as universal compatibility.
TBU405M1 40Gbps NVMe enclosure (US selection)TBU405M1 supports SSDs up to 8TB, and ACASIS advises against SSDs with heat sinks. Its speed and temperature figures are ACASIS laboratory results with named equipment, not guarantees.Sources · 2026-10-21ACASIS: 40Gbps Tool-free M.2 NVMe SSD Enclosure (TBU405 family) product pageChecked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.ACASIS: TBU405M1 user manualChecked 2026-10-21. We read the original PDF on the check date.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)Drives up to 4TB; SATA NGFF and mSATA drives are excluded. S.M.A.R.T. and TRIM support are manufacturer claims, not tested here.Source · 2026-10-21UGREEN: 40Gbps M.2 NVMe Enclosure with Cooling Fan US product page (SKU 15976)Checked 2026-10-21. We reviewed the official page text on the check date. Checkout options were not verified.
Questions to check before buying
TBU405M1 40Gbps NVMe enclosure (US selection)
The manual lists 2280 only while the product page says any size; shorter drives are not confirmed.
The manual gives two different dimension figures and no cable length or rating.
One listing sells three versions; only TBU405M1 (SKU TBU405M1-G) is represented by this record.
40Gbps M.2 NVMe Enclosure with Cooling Fan 15976 (US selection)
No CM-series model number appears in the retrieved page text; the package is identified by UGREEN SKU 15976.
Cable lengths and ratings and the drive-retention method are not stated in the retrieved text.
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