Function: The ball bearing function provides smooth operation and is very suitable for heavy doors. Opening and closing doors is easier and quieter. Application: Lubricated bearings can reduce friction caused by heavy-duty doors. Specially designed for internal wooden doors. Finish: Made of low-carbon steel, with strength and durability, and modern polished chrome finish. Suitable doors: These ball bearing docking hinges are designed for doors (including any door furniture). Fixture and accessories: This 4 hinge component is equipped with color matching screws.