Kingston Technology 4 GB Memory for Select Apple Imac's and Macbooks Single (Not a kit) 1066 MHz (PC3 8500) 204-Pin DDR3 SO-DIMM KTA- MB1066/4G at Amazon.com
DDR3 4GB Laptop Ram Memory 1333Mhz PC3-10600 204 Pins SODIMM Support Dual Channel for AMD Laptop Memory - Walmart.com
OWC 4GB PC8500 DDR3 1066MHz SO-DIMM Memory Compatible with Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, 2009/2010 Mac Mini, and 2009 iMac Models at Amazon.com
Crucial 4GB DDR3/DDR3L 1066 MT/s (PC3-8500) SODIMM 204-Pin Memory For Mac - CT4G3S1067M at Amazon.com