The SNAFU Mayweather Cranks are built with 1.4mm wall straight-gauge 4130 chromoly arms with concentric taper. One-pieced forged and broached spindle boss with two tuck pin holes. Drilled and machined 9/16-inch pedal boss with TIG-welded gusset Left-hand and right-hand drive compatible. Hollow heat-treated 4130 chromoly 48-spline spindle Grade-8 center bolts and tuck pin hardware. Works with Spanish, Mid, Euro bottom brackets, (bottom bracket sold separately).