Coleman OEM CK100 CK100-S Go kart Gas Cap; 16500/154F; Also fit predator 5.5hp 173cc engine Black plastic outside White plastic inside Cap outside diameter: 70mm [2.75"] Cap inside diameter: 55mm [2.16"] outside Chain attached to inside center of cap Rubber gasket for good seal of tank/cap This is the replacement cap for 3.0hp minibikes, mopeds, atvs... even generators. This cap fits our tank version 200 along with other 37mm notched metal gas tanks.