OWC Mercury Pro U.2 Dual Thunderbolt 3 enclosure: Versatile, fast in the right configuration

Leverage up to 8 NVMe (U.2 or M.2 with adapter) SSDs over Thunderbolt 3 with this sturdy external enclosure.

- JON JACOBI

The $300 Mercury Pro U.2 Dual is a Thunderbolt 3 storage box featuring two U.2 (a server and enterprise-level NVMe connector) bays. To add up to the eight M.2 SSDs touted by OWC, you have to use a four-slot OWC Shuttle U.2 to M.2 caddy/adapter included in the box, and then buy another adapter (fave.co/35Np4X2; $150) to max out at eight SSDs and 64TB. Or you can buy it prepopulated from OWC.

For eight drives (fastest), pricing starts at $1,500 for 4TB and ends at a whopping $12,799 for 64TB. Yup, 8TB SSDs are pricey. Note that running mirrored RAID 1 or mirrored/striped RAID 1+0 will halve available capacity.

Regardless, the bare box allows you to upgrade at your leisure and need, and the included SoftRAID XT software allows you to create RAID 0/1/1+0 arrays with any combination of drives. The SSDs may also be accessed as separate entities-that is, discrete drives.

The black metal box that is the U.2 Dual measures around 9.25 inches long, 5.75 inches tall (including rubber feet), and 3.35 inches wide. The front consists of porous grills to facilitate airflow through the two bays, with a solid strip of metal up the middle that contains the backlit logo and two activity lights.

The back is home to two Thunderbolt 3 ports (Type-C, one for daisy-chaining), a Kensington lock port, the 12-volt DC jack, and the outlet grill for the fan. To access the internal U.2 bays, you simply remove the two Philips screws from the panel, top and bottom center. The two WD 960GB 2.5-inch U.2 drives that OWC included in our test unit were secured by a single screw, though there are four holes for 3.5-inch drives and the caddies.