These Hose Deck Fills include a stainless Deck Fill Key (351399) necessary to open and close the slotted cap. Cap diameter 1-7/8", thread pitch 12 NPSM straight. Includes attachment chain. Constructed of corrosion resistant investment cast 316 stainless steel. Installs with three #10 FH fasteners (not included). USCG regulations require bonding wire to prevent sparking. Gasket sold separately (351349).