What are the different sizes of M.2 SSDs?

For SSD-based M.2 modules, the most common sizes are 22mm (width) x 30mm (length), 22mm x 42mm, 22mm x 60mm, 22mm x 80mm, and 22mm x 110mm. The card naming corresponds to these dimensions:

The first two digits define the width (all are 22mm), and the remaining digits define the length, ranging from 30mm to 110mm. Therefore, M.2 SSD specifications include 2230, 2242, 2260, 2280, and 22110.