The Synology D4ES04-4G is a 4GB DDR4 ECC SO-DIMM memory module designed for compatible Synology NAS systems. Featuring ECC (Error-Correcting Code) technology, it helps detect and correct memory errors to improve data integrity and system stability. With a 260-pin SO-DIMM design, this memory module provides a reliable memory expansion option for compatible Synology NAS environments, supporting multi-user applications, demanding workloads, and continuous 24/7 operation. As a Synology memory module, it is designed and tested for compatibility with supported systems and integration with DSM.