The aluminum bronze material works well for longevity because its a bronze and copper alloy that resists corrosion when subjected to high temperatures. It also has low reaction rate when subjected to sulfurous compounds such as exhaust. That's pretty impressive engineering. We love detail like this. Another unique part of this brake's design is that the butterfly is slightly larger than the brake housing. This allows the valve to seal completely, but with a slight off-set to the housing. This way, when the valve closes, it seals the exhaust system completely until the maximum back pressure to retard the engine is achieved. When that pressure is reached, the pressure is able to push the valve open just enough to allow the engine to run. Other brakes often use a butterfly that closes perpendicular to the housing, but use holes in the valve to allow the minimum amount of exhaust to escape. With the BD offset solid butterfly, the brake builds maximum braking pressure more rapidly.
The brake is actuated by an air compressor that was included in the kit. It mounts inside the passenger side fender well, protected by the plastic fender skirt. BD uses air compressors to actuate the brakes on newer model trucks because these trucks don't use large vacuum systems anymore. Older trucks with bigger vacuum systems can utilize BD's 3" vacuum cylinder. The exhaust brake runs automatically once the master switch has been turned on. We mounted ours on the dash on the left side of the steering wheel.