This handy template lets you make repeatable cuts correctly with ease. The dovetail is fashioned with premade convex and concave guides that fit standard measurements used in furniture making. The width of each pair of tooth bumps is the same, so by controlling the positioning of the teeth and the milling cutter, it is easy to accurately control the size of the bumps. The caliper has metric/inch scale, accurate reading and can meet different needs. After CNC machining, the caliper can provide fine scale. The caliper can operate with special milling machine Specification: Color:Black Materila:Aluminum Alloy Size:9.5x5.9x0.8cm/3.8x2.3x0.3inch Format: English / Metric Package Includes: 1 Piece Tenon Caliper Note: Please allow 1-3mm error due to manual measurement, pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item, pls understand, thank you!