This dowel jig is made by industrial grade 6150 aluminum alloy with good strength and high corrosion resistance, durable and long service life. Large clamping range, the maximum is 60mm. Comes with 9 drill rings in 3 sizes, meeting different needs in woodworking drilling hole process. Specifications Material: Aluminum alloy < p>Blue color Drill sleeves size: 6/8/10mm(3pcs/each type) Positioning peg: 6/8/10mm Suitable wood size: 17-60mm /0.67-2.36inch Size: 23.5 x 10 x 3.8cm / 9.25 x 3.94 x1.50inch < p>Usage 1. Adjust the positioning scale to determine the distance between the first hole and the end of the board. 2. After fixing the position, select the drill corresponding to the drill sleeves to start drilling. 3. Remove the scale nuts after drilling three holes 4. Use the locating pin to fix the hole on the third hole (make sure the distance of each hole is the same). 5. Drill all holes straight 6. Stick the wooden round rod with glue firmly on the punched hole Package included: 1 x self-centering centering jig 9 x centering rings drill 3 x positioning peg