AccurateDiesel 6.0L Powerstroke Billet Aluminum Fuel Filter Cap with Schrader Valve for Testing Fuel Pressure The easy way to measure fuel pressure! Built in 1/4 inch Scrader valve connects to any standard fuel pressure gauge This billet aluminum cap is the last fuel cap you will ever need (can be left in place permanently) - no more plastic caps that round off easily! Proudly made in the USA For all 2003 - 2010 6.0L Powerstroke Diesel Fits the Secondary Fuel Filter located on TOP of the engine