HP 500666-B21 16GB (1x16GB) Quad Rank x4 PC3-8500 (DDR3-1066) Registered CAS-7 Memory Kit 3rd Party by Gigaram Equivalent 500207-071, 500666-B21, 593915-B21, KTH-PL310Q/16G. This module can be manufactured by Hynix, Micron, Samsung, Elpida, Nanya, and Gigaram. This module is in stock and can ship today. 16GB PC3-8500 Quad-Rank Registered ECC DDR3-1066 240pin DIMM. The 500666-B21-MT carries a Gigaram lifetime exchange or repair warranty against manufacturing defects. It may also be returned in original condition within 14 days of delivery for full credit minus shipping. We also supply unlimited lifetime tech support for this item. 3rd Party equivalent no HP label but would be same if not better brand than HP original.