This set of 3 x 3 official PRS SE Locking Tuners fit most SE guitars and features a 1:18 gear ratio for a good balance between tuning speed and precision. The top of the string post has a locking mechanism for quick and easy string changes, simply thread the string into the string post hole and tighten the knurled thumbscrew on the post and the string is locked in place. The attachment screw is offset at a 45 degree angle to the centre of the tuner body as is common on most SE guitars and all mounting hardware is included.