Removing a gas cap can be a difficult, dirty task. And replacing one after you forget about it and drive away can be expensive. The InStant Fill's trap door mechanism accommodates the gas nozzle, eliminating the hassle of removing and replacing the cap each time you refuel. With the InStant Fill fuel cap, just insert the nozzle fully and squeeze the trigger. You'll never touch a fuel cap again! Four different models fit over 80% of the cars on the road in North America and InStant Fill meets on-board diagnostic (OBD) emission specifications, so it will not trigger the "check engine" light on late model vehicles.
Not recommended for use in areas where vapor recovery nozzles are used.