Designed to work on guitars of all styles “E-Z-Lok” are the ultimate in the quest for perfect tuning stability. Unlike ordinary tuners each E-Z-Lok post has 2 holes. This simple concept transforms each tuner into the tuner you want it to be. Want to string conventionally? then OK do it! Want to change the tension over the nut? OK, use the upper hole to decrease the tension, use the lower hole to increase the tension. Want to stay in tune when using a Vibrato / Tremolo system? Then OK, you can do this too. Eliminating the wraps around a tuner post is a “must do” when using a vibrato system. Thread the string through either top or bottom hole, pull the string tight and make a wrap around the post then thread the remaining string through the second hole pull tight again and you now have a locking tuning key. The string is now firmly attached with less than half a turn around the tuner post when tuned to pitch. For even more accurate tuning, these are the newer version with a 19:1 Gear Ratio. They require a standard 10mm Hole for mounting.