The Scepter Anti-Spill valve is a heavy-duty Scepter replacement fuel valve designed to fit all Scepter fuel cans. It prevents the overflow of petrol or oil when filling. First, remove the yellow plastic spout, thread on the anti-spill valve and depress the valve once in an upright position - this will eliminate pressure build-up in the can. Next, place the nozzle in your fuel tank and push it down. For the valve to operate correctly, there must be at least 300mL of fuel. Petrol flow will stop automatically once the tank is full. In addition, the Scepter anti-spill valve features a convenient 'lock' position to help reduce fuel spillage in the back of the truck.