The kit consists of a pair of identical 2GB PC2-5300 (DDR2-667) 240-Pin DIMM Non ECC SDRAM modules. Memory of this type was commonly used in Core 2 Duo desktop computers, and other desktops of a similar vintage. Mainstream motherboards of this era were frequently limited to 4GB of memory. It was the maximum memory usable by Windows XP and other 32-bit operating systems. This kit may therefore be of use for upgrading the memory of an old computer to the maximum extent possible.