All the needles, jets, and float valve for the Tillotson carb. This kit only works on pot metal Tillotson carbs with the bowl that is held on with 3 screws. They are also sometimes identified as model "X" or model "XF". There is a Carter carburetor that is often confused as being a Tillotson but nothing will interchange for those. The Carter can easilly be idenfified by having 4 screws holding the bowl on and several serial numbers cast into the bowl.