4GB KIT (2 x 2GB) For HP-Compaq Pro Desktop Series 4000 (Small Form Factor) 6000 (MicroTower) 6000 (Small Form Factor). DIMM DDR3 NON-ECC PC3-8500 1066MHz RAM Memory. Genuine A-Tech Brand.<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>4GB KIT (2 x 2GB) DIMM DDR3 NON-ECC PC3-8500 1066MHz RAM Memory</li><li>Genuine A-Tech Memory</li><li>Lifetime Warranty</li><li>Toll Free Technical Support 1-866-557-4527</li><li>Designed For HP-Compaq Pro Desktop Series. (See Compatibility List Below)</li></ul></div><img src="http://ecx.images-amazon.com/images/I/51%2BQ8Q%2BHa2L.jpg" noproxy>