Option Knob GloKnob-BO Boutique Glow-in-the-Dark Pedal Knob Knob Shaft Diameter Range: .235 to .25 in (5.96-6.35mm) Get some extra visibility when you're playing on a dark stage with the glow-in-the-dark Oknob Boutique Fits "boutique-style" pedals with a larger shaft Get some extra visibility when you're playing on a dark stage with the glow-in-the-dark Oknob Boutique Fits "boutique-style" pedals with a larger shaft