Brian Crower adjustable cam gears deliver the easiest way to dial in more horsepower and/or torque without getting underneath the valve cover, disassembling the engine or dealing with onboard electronics. BC gears are CNC machined from aerospace grade, 6061-T6 billet aluminum for ultimate tensile strength. Easy to read, laser etched face features micrometer style markings for precise adjustment (up to 10 degrees in each direction) and quick tunability. Each hub is held down by six ARP made, Grade-8 hex bolts for maximum clamping ability. Hard anodized finish prevents premature surface wear. Chain driven gears (SR20) feature a 1050 steel outer sprocket for added durability.