Keeping Expertise Built In , the OTR 15" x 4" Front Brake Hardware Kit has the parts your semi truck requires in order to keep your rotors and brake pads in like-new condition. This heavy duty replacement kit is recommended when new brake rotors and pads are installed in order to ensure your Anti-Lock Brake (ABS) system stands the test of time while being exposed to moisture, corrosion, and extreme weather elements. FleetPride is the First Click in Heavy Duty .