The Vintage HP 2GB PC2-6400P DDR2 ECC REG Server RAM is a single DIMM module with a total capacity of 2GB. It is designed for server use and features ECC memory for enhanced reliability. This RAM, with 240 pins and a bus speed of PC2-6400 (DDR2-800), is ideal for upgrading or replacing existing memory modules in computer servers, providing a reliable and efficient performance for server applications.