Kingston HyperX 4 GB Kit (2x2 GB Modules) 1066MHz DDR2 DIMM Desktop Memory KHX8500D2T1K2/4G 4 GB Kit including two 2 GB modules of T1 series tall profile 1066MHz DDR2 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 notebook computers From the industry leader in PC memory Low-Latency 240-pin DIMM type