Vetter double hung window. Top drops as spring is weak.
A quick learner from Lake Zurich, IL says:
April 10, 2016
Do you sell replacement springs for Vetter double hung window. Size 38 x 27.
Paul from SWISCO responded:
April 11, 2016
I'm not familiar with Vetter windows so I can't be sure. If you can, please take some pictures of your balance system so that we can try and find a good match.