Working add a brake supplemental braking unit for sale. Was used with a class c camper to tow a car. In very excellent with original paperwork and installation instructions.Unit applies brakes in towed vehicle using compressed air to push on brake pedal. Must be wired to towing vehicle brake system to activate brakes and with breakaway switch which can be purchased online. Due to size and weight this unit must be picked up in Mountain City TN. 275.00 cash OBO. No trades.