250k tone pot. From settings 1-9 it works like a standard tone then clicks in at 10 (full clockwise/ bright setting) and removes the pot and capacitor from the circuit. This eliminates the path to ground that exists with standard pots even in the full treble position. This gives a noticeable increase in brightness and output in the full treble setting. Attention: this pot is not for use as volume control. Required mounting hole diameter: 10mm.