The SK hynix 4GB 1Rx8 PC3L-12800U-11-13-A1 HMT451U6BFR8A-PB NO AA 1501 is a DDR3 SDRAM memory module with a total capacity of 4GB. It has a bus speed of PC3-12800 (DDR3-1600) and is designed for use in computers that require high-quality RAM. This product is ideal for upgrading or replacing existing memory modules in order to improve performance and reliability in a variety of computing tasks.