Block and Tackle Window Balance

Hello there. Is there a stamp on the metal channel you can show us? To be safe, can you also show us the point where the spring and pulley system connect in the 'guts' of the metal channel? I should be able to narrow this down from there. 

I'm glad you showed me this photo. You have a special configuration balance here, one that can't be replaced by one of our stock products. The clue is in the way the spring attaches to the pulley block; note that clear plastic retainer and the small rod it's holding. That may seem like a small detail, but it indicates to me a very different method of calibration. What would have happened if you used one of our stock balances is the window would be much harder to open and close, and eventually the cord would have snapped.

The good news is that can supply this balance, but only as a special order. Can you just tell me precisely how many you needed? I have to pre-set the quantity for you ahead of time. The cost per balance is $37.09 and the lead time is approximately 5-6 business weeks, as we have to get these made from scratch.