The Lot of 4 Corsair XMS2 Xtreme Performance DDR2 Memory modules offer a total capacity of 4GB with each module providing 1GB of memory. These DIMM modules are designed for high performance with features such as ECC memory, registered operation, and fully buffered technology. Manufactured by Corsair in the United States, these DDR2 SDRAM modules have a bus speed of PC2-6400 (DDR2-800) and come with a lifetime warranty. Perfect for upgrading your computer's memory capacity, these modules provide reliable and efficient performance for demanding tasks.