Sierra three-way valves are designed to manage fuel delivery from two tanks to a single engine. Click-stop detents give users a positive indication of valve position to maximizes fuel flow and allow selection from one of two tanks or shut-off to isolate both tanks. A hex head design has been integrated into the valve body to allow 31/4" NPT male fittings to be tightened while stabilizing valve. For the best possible seal, we recommend the use of a fuel resistant thread sealant when installing fittings. For a simple solution to fuel tank management, chose a Sierra three-way valve.