TonePros GKH33X 3L+3R gold guitar tuner set. Utilizing innovative new technologies and materials, the Professional Upgrade Series provides the same precision and quality TonePros is famous for. Featuring a “state of the art” 1:20 gear ratio performance inside a classic format and styling, these new tuners are “drop-in” ready and will fit most guitars without modification. The GKH33X features a metal keystone button along with a vintage flat-top post styling.