What kind of memory is this?

Most of the memory we are looking for at Free Geek, falls into one of two categories:

DIMM
Dual Inline Memory Modules are newer and longer than the older SIMMs (see below). All DIMMs are the same length, and they can be distinguished by the number and positions of their notches.

SIMM
Single Inline Memory Modules are older and shorter than the DIMMs. There are two varities, 30 pin SIMMs and 72 pin SIMMs. Both are substantially shorter than the DIMMs (below). We normally do not want to keep SIMMs these days.