Designed for their TVS-472XT, TVS-672XT, and TVS-872XT NAS devices, the 4GB DDR4 2666 MHz SO-DIMM Memory Module from QNAP is a single RAM module that will let you upgrade the overall memory capacity of your compatible NAS. It features a capacity of 4GB, a clock speed of 2666 MHz (PC4-21300), and a 260-pin SO-DIMM form factor. It operates using 1.2V, does not support ECC technology, and is not buffered/registered.