Window track

What you have here is called a channel balance. We can supply this, but yours in particular has to be a custom order due to its configuration. I need a bit more information before we can go further.

For full transparency, this exact model isn't made anymore. The good news is that there's a modern version that works in all the same applications. The catch is that the springs are calibrated slightly differently.

With that in mind, I'm going to need you to tell me the exact weight of the sash for both windows. That's the glass panel. Any common bathroom scale will do, but we need that weight down to the ounce and as precise as you can manage.

I also need a clearer photo of the metal hook at the end of the cord.

Lastly, how many of these did you need?