The clutch, in combination with the CVT / variator, transmits the power of the engine to the rear wheel. Modern 2- and 4-stroke scooters are equipped with centrifugal clutches, i.e. 2 or 3 lined clutch shoes press against the clutch bell after a certain speed is reached and thus move the wheel and vehicle. 50cc bikes with Derbi or AM6 engine, Vespa and maxi scooters like the Yamaha T-Max are, however, equipped with multi-plate clutches with 3 or more clutch discs. Motoforce, Naraku and Malossi offer high quality replacement clutches such as the Delta Clutch. For the tuning sector there are reinforced racing clutches that can adapt clutch behaviour to match tuned engines by means of various adjustment options, Stage6, Polini and Malossi are leading in this field.