Dave Sr. from SWISCO responded:
October 27, 2020
Hello, The difference between the two springs is that the 91-003 spring has a nylon clip, whereas the 91-003M has a metal clip. The springs are the same in both. However, take note I believe the metal clip is a little larger hole at the bottom of the storm sash that holds it in. You would have to file down the metal piece that clips into the bottom of the storm sash, drill the hole a little larger in the storm sash or reuse your existing nylon clip if you still have it. |