Kimtigo DDR4 16GB Laptop Dram 2666MHz (PC4-21300) CL19 (Compatible with 2400MHz or 2133MHz) 1.2V Notebook (SODIMM) RAM Non-ECC Unbuffered Single Rank 260 Pin PC Computer Memory Module Upgrade at Amazon.com
Source Fully Compatible DELL Mi-cron 4gb 8GB Ram DDR3 2133 2400 2666MHZ Server DDR4 Memory for desktop on m.alibaba.com
Amazon.com: OWC 32GB (2 x 16GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S32P) : Everything Else
Crucial 16GB Single DDR4 2133 MT/s (PC4-17000) DR x8 SODIMM 260-Pin Memory - CT16G4SFD8213 at Amazon.com
QNAP 4GB DDR4-2133 RAM MODULE LONG DIMM - Walmart.com
Amazon.com: Crucial 8GB Single DDR4 2400 MT/S (PC4-19200) SR x8 SODIMM 260-Pin Memory - CT8G4SFS824A : Everything Else