2GB RAM Memory Upgrade for the Acer Extensa 4420, 5420 and 5620 Notebook Laptops (DDR2-667, PC2-5300, SODIMM) Guaranteed Compatible for the Acer Extensa 4420, 5420 and 5620 Notebook Laptops Speed up your system with up to 4.0GB 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!