RENTHAL"TWINRING" REAR SPROCKET KTM, HUSKY, HUSABERG 125 UP ORANGE The longest lasting most durable off-road sprocket you can buy developed over 5 years. The unique flat face design keeps weight to a minimum and means the TwinRing's as narrow as a regular chainwheel. Inner Ring is high strength Ultralight 7075 T6 Aluminium. Outer Ring is Electroless Nickel Coated steel. Outer is expanded at 200 °C and then fitted to inner, creating a permanent bond for the life of the sprocket.