A dual inline memory module (DIMM) consists of a number of memory components (usually black) that are attached to a printed circuit board (usually green). The gold pins on the bottom of the DIMM provide a connection between the module and a socket on a larger printed circuit board. The pins on the front and back of a DIMM are not connected.

100-pin DIMMs are commonly found in printers. The number of black components on a 100-pin DIMM can vary, but it always has 50 pins on the front and 50 pins on the back, for a total of 100. 100-pin DIMMs are approximately 3.5 inches long and 1.25 inches high, though the heights can vary. They have two small notches within the row of pins along the bottom of the module.