M.2 - Wikipedia
https://en.wikipedia.org/wiki/M.2
M.2, formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the mSATA standard, which uses the PCI Express Mini Card physical card layout and connectors.
M.2 Interface, Key and Socket explained
https://www.atpinc.com/blog/what-is-m.2-M-B-BM-key-socket-3
An M.2 SSD is "keyed" to prevent insertion of a card connector (male) to an incompatible socket The M.2 specification identifies 12 key IDs on the module card and socket interface but M.2 SSDs typically...
Understanding M.2, the interface that will speed up your... | Ars Technica
https://arstechnica.com/gadgets/2015/02/understanding-m-2-the-interface-that-will-speed-up-your-next-ssd/
Pictured at the top of this article are four different M.2 cards. The one on the left is a combo Wi-Fi and Bluetooth card. The next one to the right is a Sandisk SSD that uses the SATA bus.
The Best M.2 Solid-State Drives for 2021 | PCMag
https://www.pcmag.com/picks/the-best-m2-solid-state-drives
Solid-state drives have been shrinking, thanks to the "gumstick" M.2 format—and, in some Here's all you need to know to buy the right M.2 SSD, along with deep-dive reviews of the top PCI Express and...