Samsung 4 GB DDR3 1333 MHz Unbuffered SODIMM 4 GB DDR3 1333 MHz Memory Module – Memory Modules (4 GB, DDR3, 1333 MHz, Notebook, 204-pin SO-DIMM, 2 X 2 gb)
4.0GB Samsung Factory Original PC3-10600 DDR3 1333MHz SO-DIMM 204 Pin CL9 SO-DIMM Memory Upgrade Module for 2011 MacBook Pro(all sizes), Mid 2010/2011 21.5" & 27" iMac, Mid 2011 Mac mini models. Lifetime Warranty.