Anodic oxidation, durable and rustproof. High hardness, rustproof, non-corrosive, suitable for long-term use. Perfect 90-degree corners: This precise clamping bracket is designed to be fixed on boxes, frames, and similar structures to assist with squaring during gluing. This right angle positioner features two additional notches. Provides true right angles for both inside and outside squares. Base and folded edges ensure straightness and parallelism. How to use: Place a square in the corner of the two pieces needing alignment and secure with clamps. Features metric and inch graduations. Precisely calibrated, easy to operate, and will not easily damage delicate edges. Available in 12cm, sold as a set of two. Professional design: Designed to attach to boxes, picture frames, shelf cabinets, and outside corners to aid in squaring when gluing. Beveled edges for easy handling and protection of delicate materials. Wide application: Ideal for creating boxes, drawers, cabinets, picture frames, furniture, and more. Many woodworkers also incorporate these into jigs and fixtures. Reliable performance, excellent utility, and efficient square alignment.