Fill It The Clean, Fast and Inexpensive Way! Now, one fueling system that can be used with 4 different tubing sizes: 1/16"", 3/32"", 1/8"" and 5/32"" I.D. Ideal for cowled engines, lightweight, no leaks, and can be used with glo-fuel and gasoline. The Fill It Fueling System features The Fill It Plug with handy knob for easy removal of fuel line to fill or drain your fuel tank. Comes with housing, 4 Fill It Fuel Line Plugs for different fuel tubing sizes, clunk and fuel tube for third line pick-up.