uxcell Potentiometer Rotary Knob Rotary Control Knob 10x12mm Hole Diameter 6mm Pack of 20 - Quantity: 20 pieces - Shaft Hole Diameter: 6mm / 0.24 inch - Color: Black and Blue - Shape: Cylindrical Thank you for viewing. I purchased these on Amazon, but they didn't fit the equipment I have, so I'm selling them. I opened the package to check the size, but they have not been used.