V-Color 32GB (2 x 16GB) ECC SO-DIMM DDR4 2666MHz (PC4-21300) for NAS Micro Server/Workstation/Compatible with Synology 21 Series 2Rx8 CL19 1.2V (TES416G26D819K-VKC) at Amazon.com
Crucial 16GB Single DDR4 2666 MT/s (PC4-21300) DR X8 SODIMM 260-Pin Memory - CT16G4SFD8266 at Amazon.com
Silicon Power DDR4 16GB 2666 MHz CL19 260-pin Laptop RAM Computer Memory SU016GBSFU266B02AF at Amazon.com
Crucial 16GB Single DDR4 2666 MT/s (PC4-21300) DR X8 SODIMM 260-Pin Memory - CT16G4SFD8266 at Amazon.com
Crucial 32GB Kit (16GBx2) DDR4 2666 MT/s (PC4-21300) DR x8 SODIMM 260-Pin Memory - CT2K16G4SFD8266 at Amazon.com
V-Color 64GB (2 x 32GB) ECC SO-DIMM DDR4 2666MHz (PC4-21300) for microservers, workstations, Networking Platforms and Embedded Systems 2Rx8 CL19 1.2V (TES432G26D819K-VC) at Amazon.com
Crucial 16GB Kit (8GBx2) DDR4 2666 MT/s (PC4-21300) SR x8 SODIMM 260-Pin Memory - CT2K8G4SFS8266 at Amazon.com