3.5 in. x 3.5 in. Satin Nickel Steel Spring Hinge with 5/8 in. Radius (Set of 2)Keep commercial doors closing safely with this 3. 5 in. x 3. 5 in. Satin Nickel Steel Spring Hinge. A standard duty steel, commercial grade door hinge, it's designed for automatic doors to securely self close. This hinge is also UL R19063 listed for A label fire doors. The hinge functions as a full mortise single acting spring hinge and has a 5 8 in. radius. UL R19063 listed for A label fire doors Steel based material Template screw hole locations