Arch Memory 2 GB (1 x 2 GB) 240-Pin DDR2 UDIMM for Lenovo ThinkCentre M52 8215-22U RAM Arch Memory is a Registered Trademark of Arch Computer, LLC 1 x 2GB DDR2-667 PC2-5300 240Pin UDIMM CL5 Dual Rank (2Rx8) Non-ECC Unbuffered 667MHz Lifetime Replacement Warranty Included