The product is a set of two OCZ Obsidian Series 2GB PC3 12800 DDR3 RAM modules, providing a total capacity of 4GB. Each module has a capacity of 2GB, with a bus speed of PC3-12800 (DDR3-1600). These DIMM memory modules are designed for high performance and reliability in computer systems, made in China by OCZ. With a form factor of DIMM and a length of 5.25 inches and a width of 1.25 inches, these RAM modules are a great choice for upgrading your computer's memory capacity.