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, 5/16, and 3/8 inch holes for specific requirements in DIY, drilling, and other woodworking tasks. Drill Perfect Holes Easily: The self-centering dowel jig features a unique positioning center design, allowing you to drill with both hands by simply attaching the screw, reducing wrist stress and enabling novices to easily drill straight and precise holes. Strong and Wear-resistant: The dowel jig is made of aluminum alloy, and the guide ring is made of high-quality stainless steel; It is strong, wear-resistant, and heat-resistant; It can withstand multiple drillings with high-speed drills and is durable. 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 must-have woodworking set for woodworkers, construction workers, and DIY wood enthusiasts. Color: As shown. Material: Aluminum. Package Contents: 1 x Dowel Jig Kit. Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to vary slightly from the real thing. Measurement may vary by +/- 1-3 cm.