Routing, Planing Accessories -Self-Centering Dowel Jig Generic Brand Highlights Self-Centering Dowel Jig Description: This self-centering dowel jig allows you to easily make butt joints, miter joints and joints Attach the jig to your work piece then use the guide to line up your holes - it's that simple The jig includes drill rings 1/4", 5/16", 3/8", 7 /16 in. and 1/2 in. Designed for easy drilling of studs requiring exact alignment Hole size is permanently cast and will not wear Specification: Material: Aluminum Alloy + Iron Clamping Range: 10-55mm Size: Approx. 12.1 x 9.7 x 6.4cm / 4.8 x 3.8 x 2.5inch Package includes: 1pc jig 2pcs 6mm sockets 2pcs 8mm sockets 2pcs 10mm sockets Note: Please use sockets drill sleeves when drilling 6/8/10mm, but no need to use drill sleeves when drilling 11/12mm. Please allow 1-2mm measurement error and color difference.