●Perfect for Acoustic Guitar, Classic Guitar, Electric Guitar, Ukulele ●Outer Diameter: 0.5 inch (12 mm), Height: 0.4 inch (10 mm), Mounting Screw Hole Diameter: 0.1 inch (3.7 mm) ●Made of steel, it is stable and durable, looks beautiful and tough enough to stand up to road life ●Easy to install and convenient to use ●Package includes: 2 pcs strap pins, felt washers, mounting screws