2GB PC3-10600 DDR3-1333MHz ECC Registered CL9 240-Pin DIMM 1.35V Low Voltage Single Rank HYNIX Memory Module Mfr P/N HMT325R7CFR8A-H9 at Amazon .com
Apple Memory Module 8GB 1333MHz DDR3 (PC3-10600) - 2x4GB at Amazon.com
A-Tech 8GB (2x4GB) RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010, Mid 2011, Late 2011), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com