The SK Hynix 4GB RAM 2Rx8 PC3-12800U-11-12-B1 HMT351U6CFR8C-PB NO AA is a single DDR3 SDRAM module with a total capacity of 4GB. It operates at a bus speed of PC3-12800U (DDR3-1600) and is designed in a DIMM form factor. With this memory module, users can enhance their computer's performance and multitask more efficiently. The SK Hynix brand is known for delivering reliable and high-quality RAM solutions for various computing needs.