This pack of six official Fender Chicken Head Amplifier Knobs have a traditional retro vibe and a sleek aesthetic that livens up the look of any vintage style amplifier, the pointed beak and indicator line make setting the knob's position as easy as can be. Introduced on tweed-era Fender amplifiers and used on '59 Bassman, Blues Deluxe, Blues Deville, Hot Rod series, Prosonic, '57 Twin, '57 Band-Master, EC Series, and Bassman TV series amps. The knobs fit 1/4" (6.35 mm) imperial solid shaft potentiometers and have set screws to tighten onto the control pot shaft.