1. Dual NVMe PCIe Adapter can add 2x M.2 NVMe SSD Slot via PCIe 4.0 x16, but also expaind extra PCIe x16 slot (x8 Signal), which can use for expanding any other PCIe Device 2.Compatible with M.2 PCI-e NVMe SSDs in all sizes:110x22mm, 80x22mm, 60x22mm and 42x22mm, 30x22mm; Not support any M.2 (-Based B+M Key) SSD; Motherboard Compatibility: Most Server and X299, X399 can support PCIe x8x4x4 Bifurcation 3.Please note: 1. 2-Port NVMe PCIe Adapter does not Support Hardware , only supports the formation of soft in Win10 , or you may build via Software, and 2 SSDs should be same model 4.The motherboard need support "PCIe x8x4x4 Bifurcation", all of the slots works in full speed. If only supports "x4x4x4x4", the expanded PCIe x16 only have x4 signal. If does not support"PCIe Bifurcation", Only the PCIe x16 works, None M.2 SSD can be recognized. 5.Please check Motherboard's user manual on its official website if you are not sure the can support Upgraded Design: 1. Two Slots of NVMe SSD are on positive and negative sides. So the card is in small size, And individual LED Indicator design show each SSD's Working Status 2. The more PCIe x16 Slot is very useful when there is no more PCIe Slot on motherboard Hardware requirement: 1. There is available PCI-e 4.0 or 3.0 x16 Slot on M/B 2. The motherboard can support PCIe x16 Bifurcation itself, and can be set as"PCI-e x8x4x4" in BIOS 3. All of the SSDs are M.2 PCI-e (M Key) NVMe SSD 4. CPU has enough channels to support Colour:Black Material:ABS Package Contents: 4 x NVMe SSD Adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.