Supplemental brakes are required by law in many states, and quite simply are peace of mind against liability if you were to be involved in an accident while towing. None of them work really well, but do aid some in the braking process. Picture trying to brake with the engine off scenario with no power brakes. Doesn't work so well. I use a Brake Buddy with my setup. It's basically a air compressor with a motion activated arm that is clamped to the brake pedal. Powered via accessory port in the dash.