This is a Western Digital Protege 40GB 3.5\" IDE HDD hard drive. It has been tested and confirmed to be in working order. The drive is compatible with internal desktop drives and supports both HDD drive types. The drive\'s model number is WD400BB and it has a rotation speed of 5400 RPM. The interface of the drive is PATA/IDE/EIDE and it is compatible with the listed categories of internal hard disk drives, hard drives (HDD, SSD & NAS), drives, storage & blank media, and computers/tablets & networking. This is a reliable hard drive that can be used for various purposes, from storing important files to running a small desktop computer.