These are Grover’s Mini-locking Rotomatic tuners (406 series) – the same innovative engineering and classic design as the original Grover Rotomatics except with reduced housing size and buttons.
These typically are designed for usage on instruments with 6-in-line tuning machine formats where spacing is limited or more clearance between tuning machines is desired. Gear Ratio = 18:1 Requires a .391 hole size (25/64 drill).
Grover’s patented locking mini-tuners have eliminated the obstacles of other locking devices. Since there are no external mechanisms to initiate the locking action, the machine head’s appearance is like any other.
623 Guitars 