The Kit “Pneumatic Braking System” or air brake or, more formally, a compressed air brake system, is a type of friction brake for vehicles in which compressed air pressing on a piston is used to apply the pressure to the brake pad needed to stop the vehicle. A drum brake is a brake that uses friction caused by a set of shoes or pads that press against a rotating drum-shaped part called a brake drum. In this kit we are using an air compressor, Solenoid Valve, and Pneumatic Piston; Air expands in Pneumatic Cylinder which produces force on the lever of brakes. Brake pads create fiction force on the rotating drum. This friction force is enough to stop the rotating wheel. www.kitsguru.com