Boat Deck Fill/Filler - Key/Keyless Locking Cap -1 1/2" Hose- Fuel Gas Marine 316 Stainless Steel Precision cast 316 marine grade stainless steel. Maximum corrosion resistance and durability in the saltwater environment. Polished to a beautiful mirror-like finish. Lift and turn tab on cap to open or close. See additional details and measurements in product description below.