Seadog Waste Deck Fill Cap Slotted Black 357018-1 by Seadog $6.70 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Seadog Deck Fill Cap Slotted #354-3570181 Waste Black Cap Only Injection molded fiberglass filled nylon. Cap threads are 1-1/4" x 11-1/2 NPSM straight.