1-3/16" L Investment Cast 316 Stainless Steel Deck Fill Key by Sea Dog®. Deck Fill Key is for use with all Fill Caps with 1-3/16" holes on center. Fits all cast stainless steel Sea-Dog® Deck Fill Caps (351320-351331 and 351350-351353). Constructed of corrosion resistant investment cast 316 stainless steel.