5 knuckle. Residential hinge available with square or radius corner. 5 knuckle residential hinge. Available in square or radius corner 1/4″ or 5/8″. 3″ x 3″, 3.5″ x 3.5″, or 4″ x 4″ sizes. C3, C4, C10, C14, or C26D finish. Product Downloads: Hinge Application Selection Guide