Air Force One (AFO) is the only supplemental braking system that includes the necessary components to meet Total Coach Protection safety regulations. With no moving parts to wear out, your AFO will stand the test of time. It is the only air brake system that energizes the towed vehicles power brakes through a patented process that doesnt require an electronic vacuum pump. It uses a pilot signal from the coach's air brake system to deliver 100% direct proportional braking