This is a hard disk drive from Western Digital. WD Caviar family provides the best combination of performance, reliability and value for today's entry-level and mainstream desktop systems. WD Caviar Enhanced IDE (EIDE) hard drives offer Ultra ATA, 5400 RPM spindle speeds, low seek times, high capacity and a 512 or 2048 KB cache buffer, all of which adds up to a fast data delivery system. And to protect your data, include Data Lifeguard, WD's exclusive automatic defect detection, and repair technology are included to enable our drives to actually fix themselves.