This carburetor choke knob set is compatible with FS100, FS110, FS120, FS200, FS250, FS130, FS55, FS80, FS85, FS83, FS87, and FS90-Z engines.Each lot contains 5 pieces.The knobs are designed to replace the choke knob on these models and restore standard choke functionality.They fit engines using part numbers 4128 182 1700 and 41281821700.