PCI Express 3.0 x16 interface, compatible with PCI Express x8 and x16 slots, support data transfer rates up to 128 Gbps.

4 x M.2 Socket 3 with M Key design, type 2242/2260/2280/22110 storage devices support(Support PCIE SSD only)

1 x M.2 FAN Power Switch
4 x M.2 access LEDs

RAID function Support:
Intel® VROC ready for X299, Z370 and Z390 Series Motherboard models. (It supports Intel® SSDs only.)
AMD® X399/X470/B450/X370/B350 Series Motherboard models*

* Maximum number of M.2 SSD support will vary, depending on different CPUs. Please see the FAQ link for further information:
https://www.asus.com/support/FAQ/1037507

20.2 * 9.6 *1.3cm