This M.2 adapter turns a regular M.2 SSD drive into a U.2 SSD. The drive can then connect to SFF-8643 connector in the system via a SFF-8639 to U.2 cable, resulting in a drive with the same performance as it would be if it had been installed on a PCIe slot.
M.2 PCIe I/F NVMe SSD to U.2 (SFF-8639) 2.5-Inch SSD Adapter with Cable