1. ACCURATE SCALE: This guitar ruler adopts high precise digital scale, which can easily measure guitar sizes such as pitch, key spacing, string spacing. 2. STAINLESS STEEL MADE: This guitar fret ruler is made of stainless steel, which is sturdy and can be used for a long time without rusting. 3. VERSATILE USE: This guitar set up gauge is suitable for all types of guitars, including electric guitar, acoustic guitar and bass guitar. 4. EASY TO USE: Simply place this guitar ruler on the head and it will automatically fall into the strings, easily and conveniently measure the size of the guitar. 5. PORTABLE SIZE: This guitar string height gauge is compact is size, easy to carry, and very practical, is a necessary tool for luthier. Item Type: String Action Gauge Ruler Colour:Black Material:Stainless steel Package Contents: 1 x String Action Gauge Ruler Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.