An air disc brake chamber is a component of an air brake system used in vehicles such as trucks and buses. It is a cylindrical device that houses the brake actuator, which is the mechanism that pushes the brake pads against the brake rotors to slow or stop the vehicle. The air disc brake chamber is typically mounted on the back of the brake caliper, and it receives pressurized air from the air brake system to activate the brake actuator. When the driver applies the brakes, pressurized air is sent to the brake chamber, which in turn pushes the brake actuator and applies the brakes.