Kingston Technology HyperX Blu 4GB 1333MHz DDR3 PC3-10666 Non-ECC CL9 DIMM Desktop Memory KHX13C9B1/4R 4GB Module of DDR3 Desktop Memory Utilizes HyperX module with faster latency timing for higher performance and speed Specifically designed and tested for compatibility in various makes and models of desktop computers From the industry leader in PC memory Non-ECC 1333MHz 240-pin CL9 Unbuffered DIMM Backed by a lifetime warranty and free technical support