High-torque exhaust in a subtle design. Provides considerably more top speed . For those who want a new silencer and want more power, but do not want to ride with a small and particularly sporty sounding exhaust on their scooter. Very good torque curve and excellent performance on 50cc and 70cc sport cylinders. Fits models with Aprilia Di-Tech Motor and Suzuki Katana Di-Tech. System comes without E-certification. Note:. If the exhaust E-certified [reduced] is delivered, the installation complies with this condition of the original engine performance and thus can be easily used as original equipment without performance enhancement. This exhaust system is restricted in 2 places: one with two spot welds, fixed directly on the manifold flange and a second small restrictor pipe in the silencer body.