Four-in-one multifunction round corner positioning tool with four different radius arc shapes, designed for common woodworking tasks. Keep workpieces consistent and reduces the need to swap shapes, boosting efficiency and through-put. Easy to install and remove: built with a locking and unlocking mechanism for quick attachment and release. Secure, user-friendly, and suitable for beginners to set up and start working rapidly. Universal type with broad applicability: compatible with a wide range of carpentry projects, including furniture edges, picture frames, and wooden components. Delivers smooth, rounded corners that enhance both appearance and tactile quality of the finished piece. Use scenarios: - Finish furniture edge corners on tables, cabinets, or countertops to a consistent radius. - Round corners on picture frames and decorative mouldings for a polished look. - Prepare small wood parts, decorative boxes, or hobby projects to achieve uniform, rounded edges.