These are the brake caliper tabs we use when building a Camburg rear end. These are designed for Wilwood's 3.5" lug spacing. They also work with radial mount calipers with the proper machined adapters. These are CNC laser cut from thick 3/8" steel and are setup to be through bolted with a 7/16" bolt. These can be MIG or TIG welded. Select your axle housing tube size and the brake rotor diameter. These are sold by the pair. These tabs work with the following calipers. Wilwood 4 Piston Superlite; Wilwood 6 Piston Superlite with adapter #250-6309; Wilwood Aero6 with adapter #250-14046; Wilwood Aero6-ST with adapter #250-14046.