Spring hinges are for automatic closing of doors Stainless Steel - Non Ferrous material 1/4" Radius Corners, 4" x 4" Full Mortise, Residential Weight - .106" thickness Furnished with Stainless Steel Wood Screws Stainless Steel Spring Hinge with Satin Stainless Steel finish. Full Mortise, Residential Weight (.106" thick) 4.0" high x 4.0" wide, 1/4" Radius Corners. Single Acting Spring Hinge is Non Ferrous. Screw holes are Staggered or W pattern (see Application Guide below for exact screw hole locations). Includes Stainless Steel wood screws (3/4" x #9 FHWS). Approved for Fire Rated Doors. Not intended for exterior outswing doors. They are light weight for residential use. BHMA Certified, ANSI 4156.17, Grade 1. Application: ANSI K51071F. Made in China