1. The spring has high strength and durability, and the opening angle is 80°. 2. Sturdy and durable stainless steel hinge, no rust, no corrosion, and durable. Invisible design, simple and practical. 3. Each package includes one left spring hinge and one right spring hinge, excluding screws. 4. For the upper lifting hardware support, it is suitable for folding beds, folding sofas, folding sofas, lifting door cabinet doors, etc.