this is a updated float for all SU H-Series carburetors H2, H3, HV3, H4, H6, HD6, HD8. Tired of the original style floats that spring an imperceptible leak and fill with fuel? We were too! Our new floats are molded from a modern, American-made material called Nitrophyl®, which is now specified for just about every modern fuel float. It will not crack or absorb fuel and is immune to a variety of fluids, including the new fuel formulations.