This HP® 726719-B21 compatible 16GB DDR4-2133MHz dual rank Registered ECC 1.2V 288-pin CL15 factory original RDIMM is 100% guaranteed to be compatible with your system and to work right the first time. Adding additional memory is the best way to increase the performance of your system. All our memory is built to strict JEDEC standards to meet or exceed the Tier 1 OEM’s factory requirements. Our products are also guaranteed by the Magnuson-Moss Warranty Act to not affect or void OEM warranties.