Vintage Set Screw Guitar AMP Chicken Head/Effect Pointer Knob, 12 Pcs Aged White 12x white Chicken Head Knobs Color: Aged White. Size: 16.3mm (height) x 30.5mm (length) x 19.2mm (Bottom diameter) Brass Insert with Set screw Fits 1/4" (6.35mm) shaft pots We will include a free wrench to adjust the screw Package Includes: 12 Guitar Amplifer Knobs 1 Wrench