These are made for the 11.75" Bronco 5 on 5.5" rotors and an inexpensive Chevy 1/2 or 3/4 ton caliper. You can use any of the 20 or so high performance calipers that share the 7" caliper pin spacing also but the Chevy seems more than good enough for nearly everyone.
These are 3/8" thick and wrap completely around the axle. If the were only partially around the axle they would be strong enough but welding the entire diameter helps control warp of the tube itself. They are available with for a 3.25" or 3.5" diameter tube.
These are ideal for all the aftermarket housings made nowadays but they can be equally usefull when trying to fit up that old Dodge or Jeep 5 on 5.5" axle, the bronco rotor will go on about any of them and if its the bolt pattern it will pretty much work...
Thanks for waiting.