The Synology D4EU01-4G 4GB DDR4-2666 ECC UDIMM RAM is a high-quality memory module designed for use in computers and networking devices. With a total capacity of 4GB and a bus speed of PC4-21300 (DDR4-2666), this RAM is suitable for demanding tasks such as data processing and multitasking. The ECC memory feature helps to detect and correct errors for improved reliability, Perfect for users looking to upgrade their system's memory capacity with a trusted and reliable product from Synology.