Two 4" x 4" (5/8" radius corner) Exterior Door Spring Hinge in Satin Nickel US15 Finish. This full mortise single acting spring hinge is recommended for use where automatic self closing of a door is required. This three knuckle hinge is adjustable and the spring tension can be increased or decreased by using the included adjusting tool. Spring hinges are fully assembled and include all necessary screws for application.