The Carlisle Brake & Friction SCL53 Series Service Brake is a hydraulically actuated, triple opposed piston, caliper disc brake designed for heavy-duty, high torque, high energy dynamic braking. Both the caliper and disc require fixed mountings. Multiple calipers may be used on a single disc to proportionately increase torque output. Most commonly used at the wheel location with 33 inch and 35 inch rims.