Hitachi HGST HTS545032B9A302 320GB 2.5" 5400 RPM 8MB Cache SATA2 3GB/s Internal HDD Hard Disk Drive 0J13963 655-1539F.Model Family: Travelstar 5K500.BModel Number: HTS545032B9A302HGST Part Number: 0J13963Apple Part Number: 655-1539FCompatible Part Numbers: H2T320854S Specifications:Form Factor: 2.5"Series: Laptop HDDInterface: SATA II, Serial ATA-300 (3.0 GB/s)Cache: 8MBCapacity: 320GBRPM: 5400 RPMHeight: 9.5mm