The Samsung 4GB Ram Pack DDR3 - M378B5773CH0-CH9 consists of two DDR3 SDRAM modules, each with a capacity of 2GB. These UDIMM modules have a form factor suitable for desktop computers and a total capacity of 4GB. With a bus speed of PC3-10600 (DDR3-1333), these Samsung memory modules are designed to provide efficient and reliable performance for your computer system.