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
SK HYNIX 16GB 2RX8 DDR4 SO-DIMM PC4-21300 2666MHZ Memory Module HMA82GS6JJR8N-VK at Amazon.com
Patriot Signature Line DDR4 16GB 2666MHz CL19 SODIMM Single at Amazon.com
A-Tech 16GB RAM Replacement for Synology D4ECSO-2666-16G & D4ES01-16G | DDR4 2666 MHz PC4-21300 SODIMM ECC Unbuffered Memory Compatible for NAS & NVR Servers at Amazon.com
Crucial 16GB DDR4 SDRAM Memory Module - for Notebook - 16 GB - DDR4-2666/PC4-21300 DDR4 SDRAM - CL19-1.20 V - Non-ECC - Unbuffered - 260-pin - SoDIMM (CT16G4SFS8266) at Amazon.com
32GB (2x16GB) DDR4-2666MHz PC4-21300 1.2V SODIMM Laptop Memory by NEMIX RAM 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
Timetec 16GB KIT(2x8GB) DDR4 2666MHz (DDR4-2666) PC4-21300 (PC4-2666V) Non-ECC Unbuffered 1.2V CL19 1Rx8 Single Rank 260 Pin SODIMM Laptop Notebook PC Computer Memory RAM Module Upgrade at Amazon.com
Kingston 16GB DDR4 2666MHZ SODIMM at Amazon.com
Crucial 32GB Kit (16GBx2) DDR4 2666 MT/s (PC4-21300) DR x8 SODIMM 260-Pin Memory - CT2K16G4SFD8266 at Amazon.com
16GB (1x16GB) DDR4-2666MHz PC4-21300 1.2V SODIMM Laptop Memory by NEMIX RAM at Amazon.com