This Kluson® 3 per side tuning machine set has imitation pearloid keystone style buttons and the improved 15:1 gear ratio for more stable and accurate tuning. The housing and button style are period correct for 1960 - 1964 production dates. These feature the standard string thru post. This set comes complete with both bass and treble side tuners, 8.8mm O.D. vintage bushings with 1/4 inch I.D. and mounting screws needed for installation.