The Samsung 4GB 2Rx4 PC2 -5300P-555- 12 -LO M393t5160QZA-CE6 is a DDR2 SDRAM memory module with a total capacity of 4GB. It has a form factor of DIMM and features ECC memory. This memory module is designed for high performance and reliability in desktop computers and laptops. With a bus speed of PC2-5300 (DDR2-667), it provides fast data transfer rates for efficient computing. The unit is a single module with 240 pins, making it compatible with a wide range of memory slots.