Retail Box, Hot Plug Drive assembly to add to or directly replace a failed 176498-B21 and others on select Compaq ProLiant servers with card edge drive storage backplanes. This drive is NOT Universal. This 36.4GB 15,000RPM Low Profile (1") Hot Swap Drive has a 4MB Cache and a Ultra320, Ultra3 and Ultra2 interface compatible with all HP/Compaq Proliant Servers listed below. Formatted Capacity: 36.7GB Compression: (Native/Uncompressed) Data Storage Device Type: SAS (Server Attached Storage) device Hard Drive Device Type: Internal hard drive Interface Type: 80-pin Ultra 320 SCSI Interface: Ultra, Ultra2, Ultra320, Ultr3, Wide SCSI Formatted Internal Transfer Rate (Min.): 26.7MB/sec Formatted Internal Transfer Rate (Max.): 40.2MB/sec External I/O Transfer Rate (Max.): 320MB/sec Average Seek Time Read: 4.2ms typical Default Buffer: 4MB Spindle Speed: 15000 RPM MTBF: 1,200,000 hours S.M.A.R.T. Support: Yes Warranty: 3-year Also available in 36GB 15k , 72MB , 147GB and 182GB Versions! Compatibility: Proliant Models: Storage System/U, 7000, 6500, 6000, 5500, 300, 1850r(450 & Below) and 850r. Other Proliants with card edge backplane but speeds may vary due to lack og Ultra2/3 controllers. Availability: Usually ships the next business day. 176498-b21oi$468.45