Black anodized billet aluminum construction. Used to upgrade from the stock caliper to a single 108mm radial caliper on the rear of your M8 Softail. Works in combination with the stock 25mm rear axle and brake rotor sizes upto 320mm. - For installing 108mm radial caliper bolt spacing - No modifications required - Fits with stock 25mm diameter rear axle - Allows upto 320mm brake rotor diameter - Radial caliper hardware kit is optional available (985741 (60mm), 985745 (70mm), 985746 (80mm). Note: The 2020-up Softail Lowrider S/ST fitment has a different mounting position/offset from other M8 Softails.