Retail Box, Hot swap Drive assembly to add to or directly replace a failed HP A6539A,A6539-63001 and A6539-69001. Our drive is Very Low Power (compared to the original), state-of-the-art design, new manufacture (not old stock) and higher reliablility. NOT BULK Package, NOT Refurb.This 73GB Low Profile (1") Hot Swap Drive has a 4MB Cache, state-of-the-art design and a Ultra320, Ultra3 and Ultra2 interface compatable with HP Disk System DS2100 and DS2300. 15,000 RPM, 146GB and 300GB upgrades now available! Formatted Capacity: 73.4GB Interface Type: 80-pin Ultra 3 and Ultra 320 SCSI Formatted Internal Transfer Rate (Min.): 57MB/sec Formatted Internal Transfer Rate (Max.): 86MB/sec External I/O Transfer Rate (Max.): 320MB/sec Average Seek Time Read: 4.6ms typical Default Buffer: 4MB Spindle Speed: 10000 RPM MTBF: 1,200,000 hours S.M.A.R.T. Support: Yes Warranty: 3-year Availability: Usually ships the next business day. A6539Ao$296.45                                             But WAIT! 146-300GB &15K Avail Upgrades: None, STD A6539Ao 73GB 10,000RPMA6539Aoi 73GB 15,000RPM(+250)A6539AoX 146GB 10,000RPM(+289)A6539AoX2 300GB 10,000RPM(+669)