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Have you heard of this protocol called UASP? It stands for “USB attached SCSI protocol.” Let’s cut out all the jargon and just say this – if a USB device supports UASP, you’ll get very fast writing and reading speeds at the same time. Transcend has a few devices that supports UASP, actually.

Transcend has external SSD Enclosure Kit – namely the TS-CM42S and TS-CM80S – that converts M.2 SSDs into a USB 3.1 Gen 1 enclosure kit. Of course, it supports UASP as well.

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Transcend also has 2.5-inch variants of these enclosures, which once again converts 2.5-inch SSDs to become a USB 3.1 Gen 1 external storage device and has UASP support as well. The enclosure for 2.5-inch drives are called the StoreJet 25S3 and also the StoreJet 25CK3.

Transcend TS-CM80S

How does UASP actually transfer speeds, you might ask? Well, the limitation is actually on the conventional way of how USB works.

Traditional USB utilizes the bulk-only transfer protocol (BOT), which allows a single, unidirectional command at a given time only. UASP allows bidirectional communication at the same time – which combined with a host computer that supports UASP, it’ll accelerate the read and write speeds to its peak performance. UASP also demonstrates up to 80% reduction in required processor resources.


Quite some time ago, we reviewed the TS-CM42S and the TS-CM80S, which supports UASP. They support SATA III M.2 SSDs, which we inserted and experienced the crazy fast speeds that UASP enables. Combined with the small, lightweight aluminium construction, the TS-CM42S and TS-CM80S is just magnificent.

Copying to and fro the TS-CM80S and PCIE NVMe SSD
Copying to and fro the TS-CM80S and a PCIE NVMe SSD

In terms of 2.5-inch SSD/HDD enclosures supporting UASP, the StoreJet 25S3 features a stylish, yet compact aluminum case, while the StoreJet 25CK3 protects your drive against shock and vibration with an outer rubber case and inner rubber shock absorber.

Transcend 2.5-inch SSD HDD Enclosure Kit UASP StoreJet 25S3 25CK3

Transcend’s 2.5” SSD/HDD Enclosure Kit comes with all the tools you need to reuse the 2.5-inch hard drive removed from your notebook. Follow the step-by-step installation guide to find useful tips and assembly instructions. The kit also features a one-touch backup function, so download the Transcend Elite software from our website to better manage your data.

Transcend ESD220C body

Besides SSD Enclosure Kit, Transcend also offers UASP supported portable storage ready to use. The ESD220C external SSD features fast data transfer rates and solid data integrity, while the Storage 25MC portable storage for PC comes with USB Type-C ports and advanced 3-stage shock protection system.

The SSD Enclosure Kit options are backed by Transcend’s Two-year Limited Warranty.


Model TS-CM42S           TS-CM80S
Form Factor Type 2242 only Type 2242 / 2260 / 2280
Interface USB 3.1 Gen 1 USB 3.1 Gen 1
Connector USB Type-C to USB Type-A USB Type-C to USB Type-A
Operating Temperature 0°C to 70°C 0°C to 70°C
Storage Temperature -40°C to 85°C -40°C to 85°C
Dimensions 81.41 x 33.6 x 7.5 mm 120.16 x 33.6 x 7.5 mm
Weight 29g 41g


Model TS0GSJ25S3        TS0GSJ25CK3
Form Factor 2.5-inch 2.5-inch
Interface USB 3.1 Gen 1 USB 3.1 Gen 1
Connector Micro-USB to USB Type-A Micro-USB to USB Type-A
Operating Temperature 5°C to 55°C 0°C to 70°C
Dimensions 129 x 79.9 x 13 mm 129.5 x 80.8 x 18.8 mm
Weight 86g 108g

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