attwood Replacement Stainless Steel 2" Deck Fill Cap with Chain - Boat Replacement Stainless Steel 2" Deck Fill Cap 66061-3 with Chain - Boat Replacement cap for 2" Gasoline or diesel fill spouts. Attaching beaded chain included with cap. High polish stainless steel Flush cap is slotted for separate key (sold separately) and features an O-ring that seals the cap watertight.