Grover is known for making the world's finest machine heads.  Includes all mounting hardware. 

The same innovative engineering and classic design as the Original Locking Rotomatics®, but with smaller buttons for those who prefer a little more space for their fingers. Gear ratio is 18:1.   Hole size .391 (25/64 Drill Bit).  These are the 3+3 configuration.  Includes bushings, washers, and wood screws - all the necessary mounting hardware.

Lifetime Warranty - Should they ever fail for any reason, simply return to Grover for a repair or replacement at no charge.