Is this a 2230 M.2 Slot?
Is this a 2230 M.2 Slot?
Scroll down a bit in this article. There’s a list of what each of the available keys are required to provide. A “key” in this context is basically a notch in a certain location, which then defines the meaning of the various pins of the connector. Some devices have multiple keys, as some of the specifications include each other (like key A+E is common, because E provides everything that A does, so a device that can work in A can always work in E as well. This specifically is often used for WiFi cards.
Sockets always only have one key though, for obvious reasons.