A quick learner from Naples Fl says:
August 22, 2016
The stamp out mark on mine is 29 9. which one should I order on your form.
Tom from SWISCO responded:
August 23, 2016
I'm afraid I cannot determine what you have based on that stamp. I recommend that you look at our Channel Balance Home Page and follow the steps in order to find the Series that best matches what you have. I also recommend weighing your sash on a scale to determine its weight. You can use that information to choose the correct option once you find the matching balance.