Arch Memory Certified for Apple 4 GB (1 x 4 GB) 204-Pin DDR3 So-dimm for MacBook Pro 13-inch Core i5 2.5 GHz MD101LL/A RAM 1 x 4GB DDR3-1600 PC3-12800 200Pin Sodimm 1.5v 1600MHz Arch Memory is a Registered Trademark of Arch Computer, LLC Lifetime Replacement Warranty Included