String ruler:
A ruler for measuring string height, frets, nuts, saddle, and other parts of a guitar.
Material: stainless steel
Size: 51mm×90mm×5.8mm
Weight: about 45g
Graduations displayed: mm and inches

The surface is used for adjusting the string height.
Hassle-free. By just holding this card to the strings, you can visually find the suitable string height.

Fritz ruler
For use on various guitars such as gut guitars, electric guitars (raise or lower string height), acoustic guitars, and bass guitars (including six string bass guitars).
The reverse side is for string spacing adjustment.
The string spacing pitch displayed is 38/40/41.5/43/45mm on guitars; 38/40/42/45mm on bass guitars (can also be used on five string bass guitars); and 50/52mm on gut guitars.

Package includes:
1 x String action ruler