M.2 SSD Physical format

[vharunsiva]

I've come across various 'M.2' SSDs online whilst researching what to get, but I've become a tad confused due to the fact that some of them have a short prong then long then another short whilst some have a short then long prong. Are they the same thing or will some not fit some ports?

 

[Barty1884]

M.2 is just a basic form factor. The specific "key" and length (2280 etc) will determine their physical compatibility.
Combine that with their actual interface (SATA vs PCIe/NVMe) will determine their outright compatibility with your system.