Delaney Square Corner 4" x 4" Steel Ball Bearing Mortise Hinge - Pair Breathe life into your old doors with these graceful ball bearing hinges from Delaney. Why settle for less when you can more, providing a discrete yet beautiful accent these quiet hinges add an exceptional touch of durability to doors that you can feel. Ball Bearing Hinge: Ball bearing hinges are designed to handle the extra stress brought on by high traffic doorways. The greased bearings reduce the rotational friction extending the life of a hinge in heavy use situations. These hinges tend to be more durable than standard, or plain bearing hinges. Material - Steel: Steel is cheap strong and durable making it a favorite for hinges of all types. Though it is more prone to rusting than solid brass or stainless steel. Mounting: The standard corners for mortised door hinges are 1/4" radius, 5/8" radius and square corner. It is recommended that three hinges be used on doors up to and including 7.5 feet with one additional hinge for each additional 2.5 feet. Make sure you check your current hinges before making a purchase. Delaney hinges come in a fine assortment of styles and finishes allowing the fashion minded home owner to easily coordinate door hardware. Sturdy construction and durable materials ensure that your hardware functions and stays beautiful for years to come.