Door hinges standard weight steel"f series -f179 class" satin chrome size 4 inch by 4 inch box of 3 hinges. RPF179 Architectural Grade, 5-knuckle architectural hinges. 4 inch by 4 inch for 1-3/8 inch to 1-3/4 inch thick doors. Steel. Conforms to ANSI/BHMA standard A156.7-2003 and A156.1-2000. Common applications in commercial and residential buildings, such as hospitals, churches, schools, airports, hotels, malls, apartment houses, office buildings, etc. Square corner hinges. Equipped with easily seated non-rising pin. Templated screw-hole patterns for use on wood or hollow metal. Include machine and wood screws, (3) 4 inch by 4 inch hinges.