GD12207 Heavy duty (10,000 cycles) extension springs have double loop ends for extra durability, 5 sizes will replace most all spring configurations on residential doors that are no higher than 7 feet. Features: -Fiberglass spring. -0.13" Galvanized carbon steel aircraft cable, installed through springs to prevent injury in case of breakage. -Length: 22". -Wood door: 10" x 7", 4 panels, 4 sections, 2 springs per door,. -Fiberglass door: 16" x 7", 4 panels, 4 sections. 4 springs on door. -Dimensions: 22.5" H x 2.38" W x 2.38" D.