Supersprox Stealth Gold 520 43 Tooth Rear Sprocket for Kawasaki Ninja EX 250 300 500 R Supersprox-stealth is about longer life, without compromising weight. Primary goal, to last 3 times longer than an all aluminum sprocket and remain as light as possible. Its about performance and function first and last. Supersprox-stealth is infinitely better than steel! You just cant achieve this level of strength on a steel sprocket with the same weight. Sure, there are light steel sprockets out there, but they cant handle the torque.