The M.2 connector, formerly known as Next Generation Form Factor (NGFF) was created to replace the older mSATA and mPCIe connectors, which it successfully did. You might be familiar with the M.2 slots on your PC’s motherboard that are commonly used to connect M.2 SSDs (NVMe or SATA), but they’re not the only devices compatible with M.2.
The M.2 connector was meant to be flexible to accommodate a wide variety of devices. So, if you have a spare M.2 slot gathering dust on your motherboard, you might want to know the types of devices you could install on it.
What I really wonder about, is I’m pretty sure my M.2 connector said something about it being in combination with some existing SATA ports i.e. if I use the M.2 connector I lose 2 or 4 of my SATA ports. Just something to keep in mind if you have already maxed out the use of your SATA ports.
See https://www.xda-developers.com/non-ssd-devices-to-use-in-m2-slot/