Each bolt in this set features a 1/4"-20 standard thread, approximately equal to a diameter of 6.35mm and a pitch of 1.27mm, ensuring a secure and durable connection. It is available in one length: 1-1/4 inch (approximately 32mm), ideal for deeper or heavier-duty fastening needs. 28pcs wood inserts, 28pcs bolts This versatile Furniture Fastener includes 28 wood inserts, 28 pcs 1/4"-20 x 1-1/4" bolts, 1 twist drill, and 2 wrenches for seamless furniture assembly. Great for constructing or repairing cabinets, bookshelves, bed frames, and other wood-based structures. The wood inserts provide a dependable anchor point for bolts, ensuring long-lasting joint strength. Wrenches included for a smoother installation experience. This set covers your essential woodworking needs for home improvement or DIY tasks. Please exercise care when using the twist drill—the tip is precision-shaped and should be handled mindfully.