Kingston Technology 8GB Kit (2x4 GB Modules) 1333MHz DDR3 SODIMM Notebook Memory for Select Apple iMac's and Macbook Pro's KTA-MB1333K2/8G at Amazon .com
OWC 8GB PC3-12800 DDR3L 1600MHz SO-DIMM 204 Pin CL11 Memory Module Upgrade Compatible with iMac, Mac Mini, and MacBook Pro (OWC1600DDR3S8GB) at Amazon .com