S&S Cycle Pinion Gear,Blue 33-4124 Each size is color-coded to match a stock equivalent gear Gears from the middle of the range are recommended for building from scratch High quality gears precision-machined, heat-treated and finish ground to different sizes for optimum gear lash Available in orange, black, red, and blue Manufacturer Part #s: 33-4121 for orange, 33-4122 for black, 33-4123 for red, and 33-4124 for blue