Arch Memory 1 GB (1 x 1GB) 240-Pin DDR2 UDIMM DDR2-533 PC2-4200 240 pin Upgrade RAM Arch Memory is a Registered Trademark of Arch Computer, LLC 1 x 1GB DDR2-533 PC2-4200 240Pin UDIMM CL4 Single Rank (1Rx8) Non-ECC Unbuffered 533MHz Lifetime Replacement Warranty Included