SAMSUNG M471A1K43CB1-CRC 8GB DDR4 2400MH Memory Module (8 GB, 1 x 8 GB, DDR4, 2400 MHz, 260-Pin SO-DIMM) at Amazon.com
OFFTEK 4GB Replacement Memory RAM Upgrade for Microstar (MSI) MS-1681-ID1 (DDR3-8500) Laptop Memory at Amazon.com
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