Product Details: Ensure your semi is ready for the journey ahead with smooth front and rear brake performance, with the OTR 1.46" U-Type Air Disc Brake Rotor with Expertise Built In™. Once the brake pedal is engaged, this replacement rotor works with the brake pads and caliper to create a compression mechanism that slows the vehicle. Fashioned with precision standards to remove imperfections and provide long-term reliability.