TonePros Kluson K33 guitar tuners are classic 3-per-side vintage style, but with TonePros engineering technology packed into the vintage box. TonePros is first in the industry again with "33s" completely sealed tuner technology applied to the vintage "Press In Bushing" format. This means that these tuning machines do not have the hex bolt around the tuner post of more modern tuners, yet these tuners are uniquely designed with extra post support and are very tight and exact in both tuning directions. 33 series tuners do not require the large hole size of either of the more modern tuners. Instead they use a more vintage-size peg hole which is either a direct retrofit or minimum modification for installation. New technology design improvements include high 16:1 tuning ratio, additional post room for extra string winds, attention to vintage weight and mass, vintage aged Butterscotch Keystone colored buttons, and high performance and quality packed into the original official Kluson name plate. 3 per side, 12/64" shaft size.Kluson has been supplying original equipment tuners to major guitar manufacturers since 1925.