USAGE RANGE this tool set is suitable for measuring all kinds of electric & acoustic guitar, electric bass, electric box guitar fretboard that measured in radians to adjust the strings piano code.GUITAR BRIDGE SADDLE NUT FILES:1.Made of high-quality steels, perfect tools filing string slots into nut and bridge.2.With 0.4mm / 0.5mm / 0.6mm / 0.7mm / 0.75mm / 0.8mm / 0.9mm / 1.0mm / 1.05 mm / 1.1mm / 1.2mm / 1.4mm / 1.6 mm different size, 25mm grinding length and 30mm length of the hilt.3.These longer-shaft files are easier to use than the shorter ones commonly available at home improvement stores9PCS RADIUS GAUGE:Color: silverMaterial: Stainless steel1 x 9 understring radius gauges ( 7.25, 9.5, 10, 12, 14, 15, 16, 17and 20)STRING ACTION GAUGE RULER:String ruler side:Material: plasticSize: 55mmx90mmx1mmWeight: about 10gGraduations displayed: mm and inchesMeasuring string height, frets, nuts, saddle, and other parts of a guitarHolding this card to the strings, you can visually find the suitable string height. ruler side:Could be used for gut guitars, electric guitars (raise or lower string height), acoustic guitars,and bass guitars (including six string bass guitars) to adjust the string space.Package Contents:1 x 9PCS RADIUS GAUGE1 x STRING ACTION GAUGE RULER1 x GUITAR BRIDGE SADDLE NUT FILESOnly the above package content, other products are not included.Note: Light 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.