Something is missing

Thank you for posting. It looks like your top sash guide is broken. I recommend our 18-166. This will keep the new balances in place once they're installed.

Now, if you agree that you have the 18-166, then I also recommend our Series 385 channel balance. I cannot guarantee that this is exactly what this window once had, but in my experience this is often used with our 18-166. Unfortunately, without the old balances, there is no way for me to know for sure what you have. That said, I think the Series 385 is a good place to start.

To determine the correct length and option, I will need you to remove the sash from the window. Then, I will need you to measure the height of the visible glass and then weigh the whole sash on a scale. Once you tell me the height of the visible glass and weight, we can work from there.

Check out the video below, as well. This will give you a good idea of how these balances operate.

The balance might be a S385-28 channel balance with a stamp option of 2750. Again, however, I cannot guarantee that this is what you have. Based on the information provided, it is our best guess.