This Billet Fuel Filter Cap & Test Kit does more than increase the under hood aesthetics on your 2003-2007 Ford 6.0L Powerstroke. This aluminum fuel filter cap features a durable, high-quality design. Over time, the factory-equipped plastic fuel filter cap can become damaged or brittle causing air leaks and other fuel system issues. For diagnostic testing, we also include a fuel pressure gauge, hose and fitting so you can install the fuel pressure gauge to the pre-installed Schrader valve for diagnostic testing.