Anderson Window Counter Balance

Thank you for reaching out to us. We believe you have a cottage window where the top sash is smaller in height than the bottom sash. In this case, I believe you will need the 24-L8-1227 balance for one side of the window and the 24-R12-827 for the other side. I recommend you replace these balance boxes one at a time since one cord is shorter than the other. I also recommend you take one balance box out and check the number code to determine what side is what. Then, install the matching balance box then do the same on the other side.