Renthal Twinring features a unique, dual-material design combining a hardened steel outer chain ring that is heated to 200°C before being permanently fitted to our Ultralight aluminum inner, creating a permanent bond for the life of the sprocket. The result is a lightweight, long-wearing rear sprocket fit to tackle any condition you can find, without adding unnecessary unsprung weight and compromising power delivery. The inner ring of the unique Renthal Twinring is engineered from Ultralight 7075 T6 Aluminum keeping the weight to a minimum, and the outer ring is made from Electroless Nickel Plated steel, ensuring an ultra long service life. Flat socket set screws prevent lateral movement between the rings in high velocity impacts. Twinring feature Renthal's self cleaning mud groove technology between each tooth preventing mud build up that traditionally leads to quicker wearing components.