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
Samsung 4GB DDR3 PC3-12800 1600MHz 204-Pin SODIMM Laptop Memory Module RAM. Model M471B5273DH0-CK0 at Amazon.com
OWC 32GB (2x16GB) PC3-12800 DDR3 1600MHz SO-DIMM 204 Pin CL11 Memory Upgrade Kit Compatible with 2015 iMac (OWC1600DDR3S32P) at Amazon.com