IKN Black Dome Guitar Knob Screw Style With Spanner for Guitar Bass, Pack of 2 Dome guitar speed control knobs for electric guitar. Body diameter:approx. 18mm/0.70inch,length: approx. 18.2mm/0.71inch. Material:steel with ABS plastic inside; Color:chrome. Hollow shaft diameter:approx.6mm/0.24inch. Package List:2 x Dome Knobs,2 x Small Wrenches.