T-H Marine Scupper Flapper Repair KitScupper Flapper Repair Kit The flapper scupper repair kit should take care of any flapper replacement job. The traditional flapper scuppers use molded rubber flappers that curl and deform over time, requiring replacement to prevent leaking. Our flappers are not rubber, but are molded of a thermoplastic elastomer that is resistant to UV and the elements, so they do not curl like the rubber flappers. Repairs most scuppers with flappers, regardless of