Black anodized CNC machined billet aluminum construction. Used to upgrade from the stock caliper to a single 108mm radial caliper on the rear of your Dyna. Works in combination with the stock 3/4" (19mm) rear axle and brake rotor sizes up to 300mm. - CNC machined billet aluminum - For installing 108mm radial caliper bolt spacing - No modifications required - Fits with stock 3/4" (19mm) diameter rear axle - Allows up to 300mm brake rotor diameter - Radial caliper hardware kit is optional available 985741 (60mm); 985745 (70mm); 985746 (80mm). Note: Please make sure you get an accurate measurement of your stock axle diameter to confirm proper fitment before ordering. Note: Caliper spacers may be needed to space off your caliper to the appropriate height depending on your rotor size.