Optibelt Timing Belt KitDriver safety should always be paramount. The wrong tension due to faulty tension idlers can cause timing belt damage and thereby result in belt failure. You should replace not only the drive belts , but also the tension and guide idler pulleys, as well as the water pump if required, in good time. In this way, you can avoid expensive engine damages.All components of optibelt KITs are selected and assembled to the highest quality standards. An 'I've been changed' sticker allows the replaced components to be marked and also distinguishes between the belt, tension pulleys and idler pulleys.