4GB KIT (2 x 2GB) For IBM-Lenovo eServer Series xSeries 226 (8488-xxx) xSeries 226 (8648-xxx). DIMM DDR2 ECC Registered PC2-4200 533MHz Single Rank RAM Memory. Genuine A-Tech Brand. 4GB KIT (2 x 2GB) DIMM DDR2 ECC Registered PC2-4200 533MHz Single Rank RAM Memory Genuine A-Tech Memory Lifetime Warranty Toll Free Technical Support 1-866-557-4527 Designed For IBM-Lenovo eServer Series. (See Compatibility List Below)