Pro Taper Front & Rear Sprockets Combo Kit. ProTaper Race Spec MX Front Sprockets: The perfect balance of weight, strength and durability. ProTaper Race Spec MX front sprockets have been CNC machined and internal broached to precise tolerances from case hardened core refined chromoly steel. Computer designed by engineers to ensure precise fitment and optimal weight savings while being perfectly balanced to allow minimal chain drag for maximum horsepower transfer without compromising strength. Finished with our proprietary coating process to further reduce wear and corrosion result in a front sprocket that is unparalleled in the market. - Core refined 655M13 nickel-chrome-molybdenum alloy steel - Internal broached and precision machined to exact tolerances - Lightening holes to reduce rotating weight - Self-cleaning mud grooves to prevent dirt build up - Specially formulated coating to retain strength and aide in wear resistance. . ProTaper Race Spec Aluminum Rear Sprockets: The perfect balance of weight, strength and durability. ProTaper Race Spec aluminum rear sprockets have been precision CNC machined to the strictest of tolerances from the highest quality alloy that has been specially formulated for off-road motorcycle sprockets. Laboratory designed by engineers to achieve maximum balance and optimization of key features like- load distribution, reduction of un-sprung rotating mass and tooth endurance result in a rear sprocket that is unparalleled in the market. - 7075-T6 Heat Treated Aluminum - Engineer designed lightening window pattern to achieve optimum balance of weight and strength - Precision CNC machined to strictest of tolerances - Exclusive ProTaper ‘angled mud groove' design every tooth on both sides - CNC machined edge chamfers and inlay for subsurface ProTaper sticker location - Countersinks to concentrically locate sprocket