High-torque exhaust in a subtle design. Provides considerably more top speed. All need a new exhaust 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 on all air and water-cooled 2-stroke engines, also fits Piaggio Purejet [injection] engines. Exhaust system comes with E-certification. Note: If the exhaust comes with an E-certification [when restricted], the system can be easily used as an original replacement without performance enhancement. In this system, the restrictor is a welded sleeve reduction in exhaust manifold. Removal significantly increases the engine power, but it negates the general operating permit (ABE).