parts-quick 4GB Memory for Synology DS220+ Compatible DDR4 SODIMM 2666MHz RAM at Amazon.com
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OWC 16GB DDR4 RAM Compatible with Synology DiskStation DS723+ and DS923+ NAS System 2666MHz PC4-21300 CL19 ECC SODIMM 2Rx8 1.2V Memory Upgrade at Amazon.com
4GB D4NESO-2666-4G DDR4 260-Pin Sodimm RAM | Memory for Synology
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Synology: Which RAM to Buy For DVA3221 NVR – Marius Hosting
Synology SODIMM ECC RAM DDR4-2666 16GB (D4ECSO-2666-16G) at Amazon.com