Western Digital Scorpio SATA 320 GB  Portable Hard Drive - Black (WD3200KTRTL) Desktop-class performance for notebook computers - With 7200 RPM spin speed, 16 MB cache, and capacities up to 320 GB WD's 320 GB 2.5-inch drives offer huge capacity for space-hungry operating systems like Windows Vista With technologies like IntelliSeek, which calculates optimum seek speeds to lower power consumption As an added layer of protection, if the drive is dropped while in use, WD's free-fall sensor detects that the drive is falling WD's ShockGuard technology protects the drive and platter surfaces from shocks during shipping/handling and in daily operation