Specification: Product Name Rotary Knob Material Plastic, Metal Color Black, Silver Tone Fit for Knurled Shaft Diameter 6mm/ 0.24" Overall Size 13 x 17mm/ 0.51" x 0.67"(D*H) Weight 21g Package Included 10 x Potentiometer Rotary Knobs Descriptions:This Rotary Knob is made of plastic material, fit for 6mm Knurled Shaft, a built in screw make it can be adjustable.
eBay