the outside is a caliper type structure. The inner brake plate is fixed on the piston pump and the outer brake plate is fixed on the outside of the caliper.
The pressure from the piston through the brake tubing pushes the inner brake vane, while the counterforce pulls the caliper to pull the outer brake vane inward.
Both press to the brake disc at the same time, and the braking force is generated by the friction between the brake disc and the internal and external brake discs.
In this process, the piston is pushed by brake fluid, also known as hydraulic fluid. This one is engine-assisted.
