O-ring and Combustion Gasket
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The fuel injector has 1 replaceable O-ring on the fuel return, 1 replaceable O-ring on the fuel injector body and 1 replaceable stepped copper combustion gasket on the tip of the fuel injector.