RAM DDR4 ECC U-DIMM 4GB
Synology 4GB DDR4 ECC UDIMM Memory Module
Technical Specifications:
Memory Size: 4 GBMemory Technology: DDR4 SDRAMNumber of Modules: 1 x 4GBError Checking: ECCSignal Processing: UnbufferedDevice Supported: Storage ServerNumber of Pins: 288-pinForm Factor: UDIMMWidth: 1.8"Compatibility: 
Synology NAS devices:  RS2821RP+, RS2421RP+, RS2421+ 
Country of Origin: Taiwan