Our Vintage-style Guitar Tuner Bushings are press-fit bushings for 1/4"-diameter string posts. Made of high quality machined brass. Straight-sided bushings: these are easier to install, and stay put better than tapered bushings. Straight-sided hex bushings are now standard on Waverly tuners. Some guitars may require peghole modification. See our specs, below. For a perfect fit, we recommend a .393" diameter reamer to cut a clean, accurate counterbore. Tip: If you are looking to retrofit tuners with 1/4"-diameter string posts into guitars equipped with larger enclosed Grover, Gotoh and Schaller machines, see our 3/8" Conversion Tuner Bushings (sold separately). Specs for our straight-sided hex bushings: Height: 0.314" (8.00mm) Outside diameter: 0.340" (8.64mm) Hex-shaped collar diameter: 0.425" (10.80mm) Sold as a set of gold 6 bushings.