1. The spring has high strength and durability, and the opening angle is 80°. 2. Sturdy and durable stainless steel hinge, rust-proof, anti-corrosion and durable. Invisible design, simple and practical 3. Each package includes a left spring hinge and a right spring hinge, excluding screws 4. For the upper support of lifting equipment, it is suitable for folding beds, folding sofas, folding sofas, lift-up door cabinet doors, etc.