The Zimmermann Brake Kit - Rear - 138903 is a comprehensive kit of products designed for the maintenance and repair of a car's rear brakes. It includes a variety of essential components that work together to ensure safe and efficient braking performance. The kit contains three main parts: brake pads, brake rotors, and brake wear sensors.

The brake pads are the main friction components that come into contact with the rotors to slow down or stop the vehicle. They are made of high-quality materials that provide excellent stopping power and durability. The brake rotors, also known as brake discs, are the flat, circular metal discs that the brake pads grip onto. They are responsible for dissipating the heat generated during braking and maintaining a smooth surface for the pads to grip onto. The brake wear sensors are small electronic devices that are attached to the brake pads and alert the driver when the pads need to be replaced.

In addition to these main components, the Zimmermann Brake Kit may also include other necessary parts such as brake calipers, brake hardware, and brake lubricant. These additional components help to ensure that the brakes function properly and smoothly. The kit is specifically designed for the rear brakes of a car and may not be suitable for use on the front brakes.

Overall, the Zimmermann Brake Kit - Rear - 138903 is a complete package that provides all the necessary parts for a complete rear brake replacement or maintenance. It is a convenient and cost-effective solution for car owners looking to maintain the performance and safety of their vehicle's braking system.