UK Made 1 piece clutch centre mod. Needed on all hard ridden and raced hayabusa's to avoid the jerky launch. Smoother clutch operation, longer transmission and chain life. It replaces the factory back torque limiter. No exhange needed. sold outright. New billet piece. Gen 1 busa's need heavy duty pressure springs and gen 2 usually use stock springs with approx 50 thou preload spacers.