The fluid reservoir stores the brake fluid that the master cylinder uses to maintain hydraulic pressure.

The master (brake) cylinder converts pressure on the brake pedal to hydraulic pressure in the brake lines.

Sensors provide the data necessary for the vehicle's computer to make decisions and monitor everything from simple vehicle information like tire pressure to complexities like the chemical content of an engine's exhaust.

The cylindrical solenoid is a relay that safely connects the high amperage battery to the starter motor when the ignition key is turned. This current then allows the engine to turn at a high enough speed to start.

The transfer case splits engine power between the front and rear axles of four-wheel drive vehicles.