Details make the difference: these beautiful strap buttons match our bridge pins, and the knobs on Waverly guitar tuning machines. They'll add a touch of class to your guitar. Each is precisely machined (none of the unsightly mold lines found on plastic buttons), and polished to accent the beauty of the material. A special countersunk brass bushing helps protect the button against overtightening — a unique StewMac feature. Button diameter: 17/32" (13.28mm) Button height: 7/16" (11.11mm)