Weber # 78960 Gas Grill Repl Control Knob for Spirit 500 & 700 Genesis 1000-5500 and Genesis Silver & Gold Prior to 2004 Model Year Weber # 78960 Repl Control Knob Replaces Weber Part # 7511 Stem Length measures 1-3/8" for older series Genesis 1000 & 2000 series grills Spirit 500 & 700 Genesis 1000-5500 and Genesis Silver & Gold Prior to 2004 Model Year Please visit Weber's website to ensure you order the correct parts for your specific grill. It is best to look up by serial #. The following link will also help you find the alpha numeric number. http://help.weber.com/schematics/#serial-number