The Sperzel EZ-mount requires no drilling for the mounting pin. There are two prongs projecting from the back of the housing that actually sink into the wood as you tighten the washer and barrel nut on to the headstock, preventing the tuning key from moving on the headstock.
Simply line up the tuning key on the headstock to look straight then hold in place as you tighten down the washer and barrel nut, it's that easy.
This is the ultimate in tuning keys. The locking feature eliminates
the need for multiple string wraps, and trem users no longer need a
locking nut that deadens string sustain and all annoying Allen screws
and wrenches (added weight). Tired of tying strings? This is the answer.
This model is proven to hold strings tightly, allowing the guitar to
stay in tune to improve playing enjoyment.
Included the bushings and washers