Amazon.com: Synology 2 Bay NAS DiskStation DS420+ (Diskless) : Electronics
parts-quick 16GB Memory for Synology DS3617xs Compatible DDR4 ECC Unbuffered SODIMM RAM (Equivalent to Synology D4ECSO-2666-16G) at Amazon.com
Synology 16GB DDR4 SDRAM Memory Module at Amazon.com
Amazon.com: DS420+ 4-Bay DiskStation Bundle with 6GB RAM and 16TB (4 x 4TB) of NAS Drives and 2TB (2 x 1TB) NVME Cache Fully Assembled and Tested by CustomTechSales : Electronics
Synology UDIMM Non-ECC RAM DDR4-2666 4GB (D4NE-2666-4G) at Amazon.com