Mostly use in amp, amplifier, effect pedal, stomp-boxes,etc. The knob has metal set screw, fits common 1/4 inch solid shaft imperial size pots, fits for most amp/pedal device and USA /Fender// standard pots If your pot is split shaft, please you know the set screw must be inserted into correct position These knobs are made of bakelite, stronger and heavier than plastic Color: Black Size: 32*14mm, hole diameter: 6.4mm Material: Plastic + brass Package Contents: 6 * potentiometer knobs 1 * screwdriver