Different M 2 Slots. Above is a picture of two m 2 slots on the motherboard of an hp stream mini. The socket can be either b or m but not both.
M 2 cards with a b key interface can only fit into a b key host slot and likewise for m key. B m or b m. M 2 to pci e x4 adapter that can take multiple lengths of drives.
Common lengths for m 2 drives and mounting right now are 30mm 2230 42mm 2242 60mm 2260 80mm 2280 and 110mm 22110.
For example 2242 as a module code means that the module is 22 mm wide and 42 mm long while 2280 denotes a module 22 mm wide and 80 mm long. One with a b key and one with a m key. M 2 ssds with b m keying maximize compatibility in both slots and will operate with 2x lanes of bandwidth. M 2 sata drives do not look like conventional sata drives and connect to an m 2 port but use the same interface and are also limited by the 600mb s cap.
