These are a new take on an old idea. Radius arms have been around a long time, I don't think Ford was the first.
The old part is simply the modification of a 4 link suspension into a 2 link with a panhard. This has been tested and true for a minimum of 30 years. What's new is the adjustability! You can fine tune both your suspension and your steering. Even if you go up in tire size these are adjustable enough to keep your caster in check.
These are made to go on 2" x .25" wall for the lower arm and use a 7/8" heim for the upper connection, I would encourage a minimum of 1.75" x .25" for the upper arm segment. Mounting distance is 2". Sold in Pairs.