These precision sanding blocks are the best tools to get fingerboards to an accurate radius.  Use double-sided tape to stick sandpaper to the block and sand your fingerboard to a uniform radius. This is especially useful when levelling pearl inlays. Radius Sanding Blocks can also be used to sand nuts and saddles to profile. - Double-sided  - Different radius on each side - 10" & 12" (250mm & 300mm) Radii - 8" (200mm) Length - 3" (75mm) Width surface - 3-1/4" (82mm) Total width - Ergonomic curved edges - Made from hard and stable American Rock Maple - High quality ABOUT FINGERBOARD RADIUS A well radiused fingerboard is essential to the setup and playability of a guitar or bass.  Having the fingerboard with a consistent radius also makes building the guitar easier as the other parts including the frets, nut and saddle can be made to the same radius without any guesswork. To use these blocks simply attach sandpaper to the surface with double-sided tape. You can start with a coarse grade and work down to fine grades while maintaining a perfect radius. Conversions- 7-1/4" & 9-1/2" (185mm & 240mm) Radii 10" & 12" (250mm & 300mm) Radii 14" & 16" (350mm & 400mm) Radii  The common radiuses tend to be - Fender electric guitars and basses - 7.25”, 9.5”, 10” & 12” Gibson guitars and basses - 12” Martin acoustic guitars - 16” Ibanez electric guitars - 16” Most acoustic guitars - 12” & 16” You can quickly check the radius of an existing fingerboard using one of our radius gauge sets