Schaller M6 PIN 6 Left Small Metal Buttons .50 Locking (Ruthenium)With the original M6 having set the standard for closed type tuning machines worldwide for half a century the new M6 offers numerous upgrades and improvements without losing its iconic halo. Since the launch of the open back GrandTune tuning machine series in 2014 Schaller's 18: 1 Velvet Tec technology has found its way onto most of the finest headstocks of the industry. Specfiications Model: 6 left Buttons: Small Metal Posts: . 50 Locking 19,5 + 21,0