03 KTM 450EXC: Pro Circuit T-4 Slip-On Exhaust (Standard) The T-4 Slip-on has an impressive design, polished aluminum canister, stainless steel mid pipe and ultra-responsive performance. Pro Circuit designed the T-4 Slip-On exhaust system demonstrating their determined commitment to the highest quality racing standards. It is constructed with stainless steel components and an aluminum sleeve. The aluminum sleeve will shave weight while the stainless steel keeps this Pro Circuit pipe running for years. Installing the T-4 Slip-On exhaust on your bike will not only shave weight, it will also boost horsepower and torque throughout the entire power curve with increased throttle response.Improved power delivery and exhaust note.Body is made from lightweight