Arch Memory 8 GB (2 x 4 GB) 200-Pin DDR2 So-dimm for HP ProBook 4510s RAM Arch Memory is a Registered Trademark of Arch Computer, LLC 8GB (2x4GB) Kit 200-Pin DDR2 800MHz SODIMMs Compatible with systems that use 200-Pin PC2-6400 SODIMM modules 8GB Memory Kit (2 x 4GB) for HP ProBook 4510s DDR2 By Arch Memory Lifetime Replacement Warranty