Product name: Torsion spring; Type: V shaped spring Durable: made of high quality steel, waterproof, rust proof and durable Process: Fine workmanship, uniform slope, high strength, strong elasticity, stable and balanced load Simple: easy to use, easy to store, easy to complete the installation or replacement process Thank you for shopping in our store. If you have any questions, please send me an email at any time. I wish you a happy life.