Toshiba Satellite L550-ST57X2 (PSLW0U) 1TB SATA 5400RPM 2.5in 9.5mm Laptop Hard Drive Replacement Size: 2.5", 9.5mm height Speed: 5400RPM, 12ms seek Interface: Serial ATA 2.6/ATA-8 Transfer Rate: Up to 3.0GB/sec