By enabling carefully calibrated slippage in the launch phase, the friction facings and cushion springs allow precision torque calibration and are therefore responsible for the gentle clutch engagement needed to start vehicles smoothly. Clutch facings are made of a number of carefully matched materials: glass or aramide fiber together with copper brass wire, embedded in a mixture of resin, rubber, and fillers. Especially when launching under tough conditions, but also under normal driving operations, the facings subjected to high friction speeds, strong clamp loads, and extremely high temperatures. During all these types of conditions, drivers still expect full performance. Clutch facings from ZF contain no lead and are manufactured via environmentally friendly processes and comply with EU vehicle recycling regulations.