4GB KIT (2 x 2GB) For HP Compaq Business Notebook nc4400 nc6320 nc8430 nx6310 nx7400. SO-DIMM DDR2 NON-ECC PC2-4200 533MHz RAM Memory. Genuine A-Tech Brand. 4GB KIT (2 x 2GB) SO-DIMM DDR2 NON-ECC PC2-4200 533MHz RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For HP Compaq Business Notebook. (See Compatibility List Below)