512MB RAM Memory Upgrade for the HP Pavilion ze5357us, ze4125, ze4145, ze4200, ze4300, and ze4500 Laptops (DDR-266, PC2100, SODIMM) Guaranteed Compatible for the following HP Pavilion Systems: ze5357us, ze4125, ze4145, ze4200, ze4300, and ze4500 Laptops 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!