Convert your 5-speed to 6-speed Reduce engine speed on highway by 14 percent (approx. 300 rpm) 6th gear is part of the shaft, strong 1-piece construction Precision machined shift drum with oversized bearings making it smooth and positive Very strong and reliable gears with core strength 35 to 45 Rockwell and surface hardness of 58/60 Rockwell This product can be used with Harley-Davidson Softail 90-97 Harley-Davidson FXR 90-94 Harley-Davidson FLT 90-97