Need to identify window balance

I'm not sure what you have, unfortunately. We have dozens of different balances with that stamp. It's not a product code or anything, it just indicates the strength of the spring.

In order to figure out what Series this is, I need you to remove an undamaged version of this balance from the window and show me clear pictures of the top and bottom ends. I especially need to see whatever shoe or clip is at the end of the cord.

Once I have those photos, I will do my best to find a good match in our inventory.

It's important to make sure the balance you show us is undamaged and as clearly visible as possible. If too many components have broken off, or if the balance is obscured by the window and frame, then we won't be able to help.