Both attic ladders in my 25+ year old house are sagging. I could not identify the manufacturer of my stairs. When the attic was closed, the springs were loose and rusty. They measured 11 to 11 1/2 inches when closed. The removed feathers were not of the same length. I bought several longer eye hooks to make up for this difference. They were easy to replace with the old hooks once the original spring was removed. key for installation. One end of the spring will need to be partially straightened to fit the hole at the end of the ladder. I used a board to keep the attic ladder closed so it couldn't fall off. When the old spring was removed I used a ratchet strap to stretch the new spring so I could hook the hook.