The Fuel Pressure on the 6.0L Ford Powerstroke Diesel is very Critical in the operation of the engine. The vehicle doesn't come with a Fuel Pressure Sensor to monitor actual Fuel pressure. The Bostech Aluminum Billet Fuel Filter Cap comes with a Schrader Valve installed that can be connected to a gauge that can accurately measure the fuel pressure. This allows you to know true Fuel Pressure and is very helpful especially in diagnosing various possible issues. You will definitely appreciate Bostech's New Solution. Try it and you will never do it the old way again!! This billet aluminum cap comes with a 1/8th tap for external oil temperature sending unit.