Perko Fuel Fill Locking InsertPerko fuel system locking insert for use with 1-1/2" vented fills. This locking insert fits most Perko vented fills and features a polymer body with zinc alloy lock cylinder. A dual purpose key opens the fill cap and locking insert.For use with the following Perko fills: 0540, 0541, 0580, 0581, 0582, 0583, 0590, 0591, and 1318. Click to Download Perko Fuel Fill Locking Insert Installation Instructions