Spring for rolling steel tempered 40/14 (40 stands for the width in millimeters and 14 stands for the thickness expressed in tenths of a millimeter)
Perforated, folded and unnerved ready to be installed without removing the shaft, complete with fixing bolt M8. For rolling high max 400.
The spring will be custom built to your roller shutter, you must ensure that the width of your old spring coincides with the width of the spring that you want to buy. (see drawing below)