DDR4
From Amazon
Corsair Value Select SODIMM 4GB (1x4GB) DDR4 2133MHz C15 Memory for Laptop/Notebooks - Black
Conrad Electronic
Corsair Value Select Laptop RAM card DDR4 4 GB 1 x 4 GB 2133 MHz 260-pin SO-DIMM CL15-15-15-36 CMSO4GX4M1A2133C15
Clove Technology
Corsair ValueSelect - 4 GB 1 x 4 GB DDR4 SO-DIMM 2133 MHz memory module