The Adata DDR2 512MB 1RX8 PC2-5300S555-12 RAM is a single module with a total capacity of 512MB and a bus speed of PC2-5300 (DDR2-667). It features ECC memory for error correction and has a form factor of DIMM with 240 pins. This RAM is designed for computers and laptops that require DDR2 SDRAM memory technology to enhance performance and speed. It is a reliable and high-quality memory unit suitable for various computing needs.