EXEDY Racing MX5 Flywheels are made from solid one piece billet chromoly steel forgings. They are specifically designed to reduce weight and inertia for better engine response. Most incorporate special design features to enhance air flow to improve the cooling of the clutch. The ring gear teeth are milled onto the flywheel unlike an aluminum flywheel where the ring gear is pressed onto the flywheel and have the possibility of separating from the flywheel. Fits all 2.0 litre, NC MX5's and less than 6kg!