Samsung 4GB DDR3 PC3-12800 1600MHz 204-Pin SODIMM Laptop Memory Module RAM. Model M471B5273DH0-CK0 at Amazon.com
Zopsc DDR2 4GB RAM 800MHz Memory Module for AMD CPU Stable Fast Data Transmission 240PIN for High Anti-Interference and Antistatic for Desktop Computer, Plug and Play at Amazon.com
OFFTEK 4GB Replacement Memory RAM Upgrade for Apple MacBook Pro 2.5GHz Intel Core i5 - (13-inch) (DDR3) (Mid-2012) (DDR3-12800) Laptop Memory at Amazon.com