M.2 Interface, Key and Socket explained

An M.2 SSD is “keyed” to prevent insertion of a card connector (male) to an incompatible socket (female) on the host. The M.2 specification identifies 12 key IDs on the module card and socket interface but M.2 SSDs typically use three common keys: B, M, and B+M

The M.2 interface

What's the Difference Between M.2 Modules?

NVMe SSD Adapter Card for M.2, X4, (1x) M.2(M Key) and (1) M.2(B Key) connectors : Electronics

The M.2 interface

M.2 - Wikipedia

M.2 (NGFF) connector pinout diagram @

The M.2 interface

Overview of M.2 SSDs

M.2 - Wikipedia

What is an M.2 SSD?