In the video, a person is seen working on a car's brake system. The person is using a wrench to loosen the brake caliper, which is a crucial part of the braking system. The brake caliper is attached to the brake rotor, which is the part of the wheel that makes contact with the brake pads to slow down the vehicle. The person is likely performing maintenance or repairs on the brake system, such as replacing the brake pads or rotor. The video provides a close-up view of the brake caliper and rotor, allowing viewers to see the details of the components and the process of loosening the brake caliper.