M2 is a PCIe 3.0 x4 interface card which was released on March 21, 2016. It is a PCIe Gen3 x4 adapter card that uses the M.
2 form factor and has the same dimensions as a SATA III 6 Gb/s hard drive. PCIe Gen3 x4 is the latest generation of PCIe and offers up to four times the bandwidth of PCIe Gen2.
Since M2 is a PCIe Gen3 x4 adapter card, it can disable any of the available PCIe slots on a computer. This means that M2 can only be used in combination with other M2-enabled components, such as other PCIe adapters or motherboards, to maximize the potential performance of your system.