CT51272BA1339 - Crucial 4GB DDR3-1333MHz PC3-10600 ECC Unbuffered CL9 240-Pin DIMM Dual Rank Memory Module

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 to each other.