Mini Warehouse Springs for rollup doors and rolling sheet doors are unique in the fact they are designed to typically have one turn when fully opened, this allows the door to remain open by keeping tension, so the drum does not unwind by itself. When the doors are closed there is more tension which helps aid in lifting the weight on the door when it is first opened from the bottom. Also, these springs have hooked ends on the coil.
Determining the correct replacement coil to by like all springs is measured by length of the coil, inside diameter and coil wire size. If the spring has a gap in the middle make sure it is compressed when measuring.
If cannot find spring your size please contact us at HERE.