Pro Circuit Ti-6 Exhaust System The Ti-6 Titanium Exhaust System is designed to improve performance and power over previous designs. Constructed of titanium throughout the head pipe, mid pipe and canister, this is the ideal exhaust for any off-road or closed course racer looking for improved performance, durability and a professional look. The Ti-6 system comes with a removable United States Forest Service (USFS) Approved Spark Arrestor making it easy to alternate between off-road and closed course riding.