Kingston Technology 4GB DDR4-2133MHz ECC, CL15, X8, 1.2V, Unbuffered, DIMM Desktop Memory (KTH-PL421E/4G) One 4GB Module of 2133MHZ DDR4 Memory Backed by a lifetime warranty and free technical support From the industry leader in PC memory Designed and tested for compatibility in various HP/Compaq Desktops (HP/Compaq):805667-B21,T0E50AA;