This sanding blocks used in guitar building and repairing, it's the perfect way to level fingerboard accurately with it. Features: Hard wood guitar fingerboard sanding block. Accurately or change a fingerboard's radius, it also suitable for gluing frets. When working on compound radius fretboard, simply change blocks as you progress along the neck. A quick visual check keeps you from accidentally altering the shape a mistake that's easy to make and hard to fix. Groove sides for comfortable grip. Specifications: Radian: 7.25, 9.5, 10, 12, 14, 15, 16, 17, 20 (optional) Material: wood Item size: 130 * 68 * 41mm / 5.1 * 2.7 * 1.6in Item weight: 252g / 8.9ounce Package size: 131 * 70 * 42mm / 5.2 * 2.8 * 1.7in Package weight: 260g / 9.2ounce Package List: 1 * Radius Sanding Block