Pro Taper's Race Spec (RS) rear sprockets are of the highest quality when it comes to materials, manufacturing processes and self-cleaning technology. The RS sprockets boast more tooth surface area, therefore are proven to outlast the competition when it comes to longevity. This is the ultimate motocross race sprocket on the market. Precision CNC machined to the strictest of standards. 7075-T6 heat treated aluminum. Proprietary mud groove design results in 44% more tooth surface area, increasing life of the sprocket dramatically. Deep penetrating anodized finish. Laser-etched teeth number for easy identification.