Installing Floating Shelves: The drill bit size is 1/2 inch x 11.8 inches, suitable for installing floating shelf brackets and hidden shelf brackets less than 9 inches; ideal tool for installing hidden brackets. Extended bit size fits most common floating shelf sizes. Multi-purpose: Our dowel jig kit can drill 1/2-inch holes for installing floating shelves, hidden brackets, and mantels, and can also drill 1/4-inch, 5/16-inch, and 3/8-inch holes for various DIY, drilling, and woodworking tasks. Drill Perfect Holes Easily: The self-centering dowel jig features a unique centering design that allows two-handed operation by simply attaching the screw, reducing wrist strain and enabling users to drill straight, accurate holes with ease. Strong and Wear-resistant: The dowel jig is made of aluminum alloy, and the guide ring is constructed from high-quality stainless steel. It is durable, wear-resistant, and heat-resistant, capable of withstanding repeated use with high-speed drills. Meet Diverse Needs: Value set includes 1 dowel jig, 4 drill sleeves (6 mm, 8 mm, 10 mm, 13 mm), and 4 drill bits (1/2 inch, 1/4 inch, 5/16 inch, 3/8 inch), making it a practical woodworking set for woodworkers, construction workers, and DIY enthusiasts. Color: As shown. Material: Aluminum. Package Contents: 1 x Dowel Jig Kit. Note: Light reflection and different displays may cause slight variations in the color shown in the picture compared to the actual item. Measurement may vary by +/- 1-3 cm.