The Power Spout screws directly on to the pull out spouts found on VP Racing Fuels 5 Gallon Pails making the transfer of liquids much easier. The 1/4" vent tube allows air to flow in to the bottom of the container releasing the internal pressure resulting in a smooth and quick pour. NOTE: VP Power Spouts are designed to ONLY fit VP Racing Fuels 5 Gallon Pails