DescriptionMade by material, can be used to accurately measure fret board radius, saddle radius nut radius from either the or the bottom radius surface. It canprotect your guitar fretboard when filing, sanding, polishing and using.Feature-Color: Silver. - Material: Metal. - Size: 7 x 6.6 x 0.6cm. - Widely Used: Can be used for most kind of guitar, includedelectric guitar, electric bass, acoustic guitar, electric box guitar. - Made by material, durable and have long service life. -Can be used to accurately measure fret board radius, saddle radius nut radius from either the or the bottom radius surface.Warm Tip: Dear buyer, Due to lighting effect, monitor's brightness, manual measurement and etc, there could be some slight differences in the color and size between the photo and the actual item. Sincerely hope that you can understand! Thank you!