The Zone Offroad knuckle component box for 2021 Ford F-150 specifies driver-side knuckle parts for that model year. This knuckle box supplies the driver-side (DS) kit segment used during the front suspension modification and is intended to be used with the complementary passenger-side box and other kit components to complete the work on supported 2021 F-150s.
Zone Offroad 2021 Ford F-150 Knuckle Box Kit - DS