Akrapovic - S-PI3SO3-HRSS - Slip-On, Hexagonal Titanium Scooter Muffler - Silver Slip-Ons represent the first step in the exhaust system tuning process, and they offer a great balance between price and performance. Change the nature of your bike by adding more power, improved performance, and the unique Akrapovic sound. Everything packed in stylishly designed Slip-On exhaust systems. Race-proven materials. EC type-approval is valid only when catalytic converter is installed.