Arrow 71686MI Racing Collector Pipe for Kawasaki Z 400 19-20/Ninja 400 18-20Arrow Exhaust Headers Kawasaki Ninja 400 Not all exhaust pipes are made equal, the Arrow Exhaust Header bears all of Arrows experience accumulated from world class racing. That experience has lead Arrows to fine tune each part of their design and manufacturing processes. Everything from pipes diameters, sections bends, components, welding and layout are carefully tested to produce a product with high performance, reliability and last but not least,