Yoshimura Rs-4 Slip-On Exhaust Husqvarna / KTM 350cc-500cc The Yoshimura Rs-4 Slip-On exhaust has been put to the test and has proven its capabilities at the highest level of competition. In 2010 the Rs-4 muffler helped Ryan Dungey claim the AMA 450 Supercross and Motocross championships in his rookie season. The Yoshimura-backed Geico Honda team also took home both East and West Coast Supercross Lites titles in 2012 using the Yoshimura Rs-4 exhaust. Utilizing the same R&D that helped bring success at the national level has resulted in a unique exhaust design that provides an unrivaled combination of power and quiet exhaust note. The Yoshimura Rs-4 Pipe features an innovative carbon cone end cap, a two staged stepped baffle, and a polyresonant duplex chamber which acts as a muffler within a muffler to help save weight and centralize mass. Nearly all Yoshimura exhaust systems that have won Motocross or Supercross championships are members of the Yoshimura Signature Series. All Signature Series pipes have been tested, documented, and marked as required by federal and state regulations. Working in conjunction with factory race teams has allowed Yoshimura to develop a exhaust system that gives you an unparalleled competitive advantage. Features: Pentagonal-shaped sleeve Polyresonant front muffler chamber which helps reduce noise Two-stage stepped baffle Yoshimura Signature Series muffler Carbon fiber end-cap Carb/Epa tailpipe emissions compliant 100 Made in the USA