TonePros Kluson KB3 guitar tuning machine was inspired by today s professional guitarists who want to retrofit newer guitars for vintage mass and tone. Now even older instruments that have been modified can be returned to a more vintage weight and mass. TonePros now makes this possible with high technology and quality, with a new 15:1 Tuning Ratio, quality gear components, and the tightest tuning feel of any tuner of this format. TonePros Kluson B3 tuners fit any guitar with 25/64ths large hole/bolt bushing format without modification. B3 series tuning machines come with the same vintage Butterscotch Keystone buttons of the 33 series. Expect improved tuning performance with vintage appearance. 16:1 gear ratio, 25/64" shaft size. Retrofit your vintage guitar with no modification.