Samsung 4GB DDR3 PC3-12800 1600MHz 204-Pin SODIMM Laptop Memory Module RAM. Model M471B5273DH0-CK0 at Amazon.com
Amazon.com: Crucial RAM 16GB Kit (2x8GB) DDR3 1600 MHz CL11 Memory for Mac CT2K8G3S160BM : Everything Else
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
Single 16GB DDR3L 1600MHz PC3L-12800 SODIMM Memory (for 5th Gen 6th Gen i3 i5 i7 Laptop only) RAM (PARTS-QUICK Brand) at Amazon.com
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com