8GB (1x8GB) DDR4-2666MHz PC4-21300 ECC UDIMM 2Rx8 1.2V Unbuffered Server Memory by NEMIX RAM
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