Seagate Constellation ES ST1000NM0001 1TB 3.5" 7.2K 7200RPM 64MB Cache SAS 6Gb/s HDD Hard Disk Drive 9YZ264-039.Seagate Model Number: ST1000NM0001Seagate Part Number: 9YZ264-039IBM Part Number: 49Y1903 1P49Y1903Lenovo Part Number: 49Y7462 11S49Y7462Compatible Part Numbers: 49Y1939 49Y1930Specifications:- Form Factor 3.5" - Capacity 1TB- On-Board Cache 64MB- RPM 7.2K- Average Seek Time 8.5 ms- Drive Interface Type SAS 6.0GBpsFeatures:- Low Halogen Design- Drive Self Test (DST)- Embedded Servo Design- PowerChoice Technology- Background Media Scan (BMS)- Idle Read After Write (IRAW)- Dedicated Head Load/Unload Zone- Perpendicular Recording Technology- Programmable Auto Write and Read Reallocation