Made from premium, durable steel material for heavy-duty and longer life use Blue zinc-plated and electro-galvanized finish for higher rust and corrosion resistance in any condition Designed for internal doors, the tension of the spring in the roller catch holds it in the metal keep, ensuring the door is held in the closed position Very simple and easy to install The adjustable mechanism allows for wider application, suitable for doors that require varying degrees of closing strength They can also be used where there is a large gap between the door and the frame