ThinkSystem ST650 V2 3.5" NVMe 4-Bay Backplane Kit
This option kit comes with the following components.

1 One 3.5-inch hot-swap AnyBay 4-bay backplane
2 One SlimSAS x8 to MCIO x8 pair (820 mm/780 mm)
3 One SlimSAS x8 to MCIO x8 pair (325 mm/160 mm)
4 One 3.5-inch backplane power (400 mm)
5 One SlimSAS x4 to SlimSAS x4 (540 mm)
6 One label (NVMe)
See Install server hardware options for more information to install the option kit.