O-ring and Combustion Gasket
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. 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.