The Hynix RAM 4GB (2GB x 2) PC2-6400S is a set of two DDR2 SO-DIMM memory modules with a total capacity of 4GB. Each module has a capacity of 2GB, and they operate at a bus speed of PC2-6400 (DDR2-800). Made by Hynix, a well-known brand in the memory industry, this RAM is ideal for upgrading the memory capacity of laptops and other devices that use DDR2 memory technology. Originating from Korea, South, these memory modules offer reliable performance and are a cost-effective choice for improving computer speed and efficiency.