The Star Tech.com DRW150ATABK lets you quickly add & remove your ATA66, ATA100, or ATA133 hard drives without having to power down your computer. Perfect for switching between multiple operating systems, making high-speed, high-capacity backups or for mission-critical PCs or servers, this two-piece removable storage unit consists of an outer bay that mounts into a 5.25" bay on your PC, & a removable drive caddy that holds your ATA drives. To protect your important data, the DRW150ATABK features a locking mechanism to prevent the drive from being accidentally removed while in use & a built-in alarm that alerts you if your drive temperature gets too high. The drawer's dust-resistant door prevents dust particles from entering your computer & the cable-less internal connector allows increased flexibility & a longer product life.