Baldwin Square Corner 4.5" x 4.5" Solid Brass Ball Bearing Mortise Hinge - Single HingeBaldwin's top of the line hinges set industry standards for excellence. These durable hinges are available in several finishes and are strong enough for light commercial use, bringing the dependable performance you need wherever you need it.Manufactured from solid brass extrusions for both exceptional strength and precision tolerances, Baldwin hinges are individually machined from a solid brass bar resulting in a high quality hinge with increased wear performance. Each hinge is beveled on the inside leaf to obtain a perfect fit when closed.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 - Solid Brass: Solid brass is made from copper and zinc and is prized for its resilience, durability, and beauty. Solid brass can always be polished back to its original sheen and is highly resistant to rusting. Solid brass is often available in finishes that other hinge materials are not.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.There are brand names, and then there is Baldwin. Constantly building and re-building upon a time tested legacy of superior design, craftsmanship, functionality and innovation, Baldwin Hardware has delivered modern luxury to discriminating homeowners, architects and designers since 1946. From being the first to forge solid brass door hardware to setting precedence for Lifetime Finishes, Baldwin has been and always will be synonymous with revolutionary technology and unsurpassed quality. Aspire to make your home much more than mere shelter, and relax in the assurance that function and elegance can finally flourish within the same line of fine products—Baldwin can show you how.