The Zimmermann Brake Kit is a comprehensive set of products designed for use on a car's front and rear brakes. It includes four high-quality brake rotors, four sets of brake pads, four brake calipers, and all necessary hardware for installation. The brake rotors are responsible for providing a smooth surface for the brake pads to grip onto, while the brake pads use friction to slow down and stop the vehicle. The brake calipers house the brake pads and are responsible for applying pressure to them. This kit is designed to provide optimal performance and durability for the car's braking system.