FEATURES: Ball bearing hinges are popular due to their smooth operation, durability, and ability to carry heavier loads than standard hinges. 1 pair generally used for internal doors and 1.5pairs for heavier wood or glazed doors FIRE RATED: To help prevent the spread of fire by ensuring doors remain closed in the event of a fire, these hinges have been approved in accordance with the BS EN 1935 standards, making it suitable fire and smoke door assemblies.