These bushings are used for installing Vintage tuning keys on modern 10mm tuner holes. (Normally the vintage guitar tuner bushings are 8mm diameter)[MATERIALS].This guitar conversion bushings is material, durable and long service life.[APPLICATION]The guitar conversion bushing is a common tool for guitar repairman.It can use for installing Vintage tuning keys on modern 10mm tuner holes.[FINE WORKMANSHIP] Tuning Key Bushings have small body and it has great performance.Excellent product process ensure the edge of the smooth and structured.[PRODUCT SPECIFICATIONS]12 x Guitar Tuner Conversion Bushings Adapter Ferrules.The outer diameter is about 14.3mm.The inner diameter is about 10 mm.Material:plasticcolour:SilverPackage Contents:12 x guitar tuner bushingsOnly the above package content, other products are not included.