2GB PC8500 204PIN SODIMM 1066MHZ DDR3 SDRAM. Genuine CMS brand, CMS is one of the most trusted names in the Computer Memory industry and this product carries a Lifetime Warranty from CMS Maximum Memory: 8 GB Expansion: 2 Sockets COMPATIBLE WITH: Panasonic Toughbook 52 Mk3 CF-52 Panasonic Toughbook 52 Mk3 CF-52Mxxx Panasonic Toughbook 52 Mk3 CF-52Nxxx Panasonic Toughbook 52 Mk3 CF-52Pxxx Panasonic Toughbook 52 Mk3 CF-52Qxxx If 4GB is installed, the recognized memory may be reduced to 3.5GB or less with 32-bit operating system.(depending on system configuration and memory allocation). Maximum configurations require a 64-bit operating system.