Wintec AMPX MHzCL5 4GB(2x2GB) UDIMM Kit 2Rx8 1.9V with HS 4 Dual Channel Kit DDR2 800 (PC2 6400) 240-Pin SDRAM 3AXT6400C5-4096K Storage Capacity: 4GB Technology: DDR2 SDRAM Form Factor: DIMM Compatibility: Desktop