Crucial RAM 32GB Kit (2x16GB) DDR4 3200MHz CL22 (or 2933MHz or 2666MHz) Laptop Memory CT2K16G4SFRA32A at Amazon.com
Samsung ram Memory 4GB (1 x 4GB) DDR3 PC3-12800,1600MHz, 204 PIN, SODIMM for laptops 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