The perfect knob for your effect pedal!  It with a 3/4" overall diameter it won't take up much space on your pedal (or guitar for that matter).  The 1/4" mounting diameter will fit any split-shaft or solid-shaft pots.

Direct replacement for many pedal manufacturers knobs.

Overall knob diameter:  .75" (19mm)

Knob Height:  .49"  (12.5mm)

Shaft Mounting diameter:  .25" (6.35mm)