The Voith 115 CT is a step-up gear retarder with a high braking torque. It has a self-contained oil supply system and is integrated into the vehicle’s braking management system. In conjunction with the service brakes, it provides optimal braking action. At the same time, the retarder increases riding comfort, for example via the v-constant function that keeps speed constant downhill, in the same way as downhill cruise control, without the additional use of the service brakes.