This rotary knob is made of plastic material, metal hole of 6mm, a built-in screw makes it can be adjustable. Potentiometer The rotary knob is useful for connecting the rotary potentiometer, usually a multi-turn linear potentiometer which still serves as a volume control switch. Groove handle design, switch more convenient. Plastic control knob to assemble with a potentiometer for easier rotation. A type potentiometer volume switch, clockwise and counterclockwise rotary control. The replacement part for the audio device, the 6mm shaft can be easily pushed onto the 180 degree rotary knob to easily control the potentiometer.Specifications: Material: plastic, metal Color: black Suitable for shaft hole diameter: 6 mm / 2.3 inch Button top diameter: 27 mm / 10.6 inch Height size: 16 mm / 6.3 inches Rotation angle: 180 degrees Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing.The measurement error allowed is +/- 1 to 3 cm.