FRONT SPROCKET: 4035 K teeth number : 13 16CrNi4 Steel REAR SPROCKET: 2085 E teeth number: 56 ightened aluminum alloy 7075T6 crown CHAIN: 428MXZ plates number: 132 Designed for motocross racer, lighter weight but stronger chain compare to Heavy Duty Chain. Feature chromoly steel construction with seamless rollers and bushings, and oversized special ally pins for added strength