512MB RAM Memory Upgrade for the Dell Dimension 2350, 2400, 4550 (DDR-266, PC2100) Guaranteed Compatible for the following machines: Dell Dimension 2350, Dimension 2400 and Dimension 4550. Speed up your system with up to 1.0GB of Memory! Lifetime Replacement Warranty! Will ship the same day when ordered at or before 4pm EST! All others ship next day! Fully-staffed call center to help with installation or inquiries! Call 866-335-1355 with questions or for help!