The TRP HY/RD road brake is a model that can be fitted to the front or rear of road bikes, cyclocross bikes and gravel bikes. These brakes use a mechanical-hydraulic hybrid system. The piston is actuated by a cable every time the lever is pressed and a hydraulic reservoir is integrated, which controls the effect of the brake pads when the piston is applied. In this way, the braking effect is stronger. The HY/RD road brakes: Open hydraulic system / Integrated master cylinder / Thermally insulated hybrid pistons ... The HY/RD brakes have a closed hydraulic system that runs on mineral oil, which guarantees a long service life. This TRP part offers unique performance control without the need for adjustment. This bolt is 100% stainless to provide you with a long-lasting quality product.