Polini Racing & replacement exhaust systems are always manufactured for top quality and performance. The Italian manufacturer tests and develops its systems in its own development department and demands the highest standards from its products. This exhaust is in this format has been specifically designed for scooter-cross applications. Caution! The Big Evolution exhaust systems are specifically designed for the Big Evolution of cylinder kits, top squeeze every last drop of performance from your engine. . To withstand the higher compression of the cylinder, a special exhaust flange with 3-point attachment is used. Therefore Big Evolution systems should only be used with Big Evolution cylinder kits. Specifically designed for scooter-cross applications. The exhaust provides more ground clearance. The supplied bracket also fits onto the optional Polini Torsen WD swingarm. This gives the necessary stability with highly tuned engines by relieving the load on the crankcase.