Beckson Screw Type 1" Drain Plug Screw-type drain plug with patented self-cleaning thread design, O-ring, and super strength center retaining legs to secure the center while draining. Ideal installation for transom of personal watercraft, small boats, fish wells, coolers, ice chests, water tanks, etc. Part should be mounted in a 1" ID hole with two S/S fasteners and positioned with gap in thread at lowest point.