This is a set of 3 metal control knobs for electric guitars and basses. They are easy to attach with sleeves included. I'm not sure of the exact specifications, but I believe they are metric. There are some minor scratches on the surface, but they are generally in good condition. I am also selling other parts, so please feel free to contact me if you are interested in purchasing multiple items. Thank you for looking. #guitar #bass #parts #metal_knob #chrome #control_knob