High qualityMade of high quality alloy steel material, high hardness, strong and durable. AccuracyFast and accurate the arms of the jig are an always-reliable parallelogram that never fails to find dead center. Simply align the precision-machined notch on the jig's center bar with the dowel location mark on your board, hold the jig and drill. Sizes1/4-Inch, 5/16-Inch, 3/8-Inch, 7/16-Inch and 1/2-Inch, suitable for creating different wood pin joints. ApplicationConvenient and practical with the practical joinery punch locator, you can more conveniently work for woodworking. Package1Pcs doweling jig self centering and 6 Pcs three sizes hardened steel bushings. Specifications: Material: Carbon Steel, Aluminium Alloy color: as show Tools Size: 120 x 64mm / 4.72" x 2.21"(L x W) Bushings size: 2 x 1/4", 2 x 3/8", 2 x 5/16" Acceptable wood thickness: 10mm-55mm / 0.39"-2.16" Distances Adjustment Instructions: Firstly, Unscrew the two left screws with the hexagon socket. Second, Adjust the large screw on the middle rod to make the left and right distance of the product consistent. Thirdly, After the left and right distances are the same, tighten the left two socket head cap screws. Finally, Rotate the small rotating rod, and check whether the left and right distances are uniform in the experiment. Package Lists: 1 x Doweling Jig 6 x Bushings