Single hung spring balance

A quick learner from Dublin, CA says:

We have a non-titling double pane window. Thread of one of the support side channel broke and we need to replace the supporting channel. The channel itself doesn't have any brand name or dimensions. I have attached few snapshots and hopefully you will be able to help me. Thanks

User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
Hey, thanks for posting. I've narrowed this down to two possible channel balance Series: either our Series 380 or our Series 385 balances.

Now, as you can see, there is only one difference between these two Series, and that is their bottom shoe. The Series 380 uses the 15-005 while the Series 385 uses the 15-004. I can't quite tell what you have based on your pictures, though. Please carefully compare their dimensions to your own hardware and see which is a better match.
15-004 and 15-005
I will also need you to confirm the weight of your window sash so that we can recommend the appropriate stamp option, as we do not have a match for 29-9.
A quick learner from Dublin, CA says:
Hi Tom,

Thanks for your response. I checked the bottom shoe and it looks I will need to go with 15-005. I measured the depth and its 1 inch (same as in 15-005). I have below attached a snapshot of the bottom shoe.

Also I am not sure the weight of window stash. However I know the windows are pretty heavy and are doubled paned.
Profile picture of Tom
Tom from SWISCO responded:
Great, glad you were able to find the right shoe. Unfortunately, we cannot recommend a stamp option without knowing the exact weight. We do show a list of each option available for the S380-30, so all you need to do is weigh your sash on a scale and compare it to this list. It is important that you get as precise a weight as possible. We do not recommend estimating.
A quick learner from Dublin says:
Hi Tom,

Thanks a lot. Finally found time to remove the window and weigh it. It weight about 40 lbs. So I am going to order S380-30 / 2965 stamp.
Profile picture of Paul
Paul from SWISCO responded:
To be honest, 2965 may not be enough. It can only carry 39 pounds, maximum. You may want to check out this Custom Channel Balance Request Form I've started for you with a 2970 option. Once you fill out the blank fields and submit, one of our representatives will get back to you with a price quote and an item to add to your cart.
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 4-7 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at 856-317-6263 or at