Samsung M471A1K43BB0-CPB 8GB PC4-17000 DDR4-2133MHz Non-ECC Unbuffered CL15 260-Pin SoDimm 1.2V Single Rank Memory Module - OEM at Amazon.com
Micron MTA4ATF51264HZ-2G6E1 Non ECC PC4-2666V 4GB DDR4 at 2666MHz 260pin SDRAM SODIMM Single Kit Laptop Memory - OEM at Amazon.com
Micron MTA4ATF51264HZ-2G6E1 Non ECC PC4-2666V 4GB DDR4 at 2666MHz 260pin SDRAM SODIMM Single Kit Laptop Memory - OEM at Amazon.com
Samsung 4GB DDR4 3200MHz PC4-25600 1.2V 1R x 16 SODIMM Laptop RAM Memory Module M471A5244CB0 at Amazon.com
Amazon.com: OWC 8GB (2 x 4GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S08P) : Everything Else