Feature:Size: Set of 8pcs includes 4 narrow radius gauges and 4 wide radius gauges in 7.25 inch, 9.5 inch, 10 inch, 12 inch, 14 inch, 15 inch, 16 inch, 20 inch radii.Material: Made of Acrylic so that it is stable, durable and widely used.Accurate, convenient, pocket-sized measuring tool.Portable:Handy when you want to check a fingerboard without taking the strings off.It's faster to use than any ruler, and stays parallel to the fingerboard-much easier than trying to hold a ruler perpendicular to a rounded fret.Applies to:7.25 inch compatible with electric guitars with a relatively large arc or ukulele 9.5 inch compatible with Fanta electric guitars;10 inch compatible with Gibson electric guitar;12/14/16 inchcompatible with acoustic guitar;18/20 inch compatible with classical guitars,Fit compatible with string instruments such as electronic guitar, bass, acoustic guitar, mandolin, banjo etc.Colour: BlackMaterial: AcrylicPackage Contents: 8 x Radius Gauge Ruler ( 4 x narrow and 4 x wide radius gauges)Only the above package content, other products are not included.Note: Light shooting 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.