AAF Mini R53 Brake Backing Plates (Pair) Made for 2.5″ tubing AAF High Efficiency Brake Cooling Backing Plates use a unique shape and manufacturing process to keep the features needed for optimum cooling while keeping cost and weight low. All of the incoming cool air is used in a focused manner not only to feed the center of the rotor, but to feed cool air directly to the pads, the caliper’s inboard puck/dust boot and shield, and steering and suspension pick up points. Quality steel construction that comes in at only 15 oz and at an affordable price will meet the cooling and budget needs of your entire front brake assembly.