SODIMM stands for Small Outline Dual Inline Memory Module. This 512MB DDR PC2100 200-pin SODIMM is used to provide DDR SDRAM memory for laptop computers. Each 200-pin SODIMM provides a 64-bit data path, so they are installed singly in 64-bit systems.200-pin SODIMMs are available in PC2100, PC2700 & PC3200 DDR SDRAM. To use DDR memory, your system motherboard must have 200-pin SODIMM slots & a DDR-enabled chipset. The number of black components on a 200-pin SODIMM may vary, but they always have 100 pins on the front & 100 pins on the back for a total of 200. 200-pin SODIMMs are Approx. 2.625" long & 1" high.