Front Inner / Outer Axle Steering Knuckle Seal is a direct fit for the following:

1999-2004 Ford F-250 Super Duty
1999-2004 Ford F-350 Super Duty
1999-2004 Ford F-450 Super Duty

1999-2004 Ford F-550 Super Duty

With 4x4 & 50/60 Dana Axle