Need ribbed window track not sure what type of window they are

A quick learner from Wisconsin says:
May 10, 2020
Ok here is the skinny. Older Wausau Home 25 years approx. Home has several tilt out window channels not working or broken. Took out part and measured length is 31 and eighth. However the stamp says 28HB. So really nothing is matching up on your replacement parts. Was thinking what you have to order is a 31 length but no numbers matching up. Please help
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Tom from SWISCO responded:
May 12, 2020

That stamp is very peculiar, but stamps aren't product codes or anything. They just indicate the strength of the spring. In order to identify the Series, we need to go by its physical attributes.

I will need to see a picture of the other end of the metal channel as well as a picture of whatever clip, hook, or shoe is at the end of the cord. I would also like the exact weight of the sash.
A quick learner from Wisconsin says:
May 12, 2020
I have no idea what the weight is but almost 3 feet across so thinking heavy estimating 20-25 lbs. Its a ribbed channel with metal clip.
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Tom from SWISCO responded:
May 13, 2020

That's the top end taken care of, but we still need the rest of the information I requested. I also wouldn't recommend estimating the sash weight. In my many years doing this I've never seen anyone guess right. It's best just to get the exact weight to be 100% sure.
31" Series 751 Channel Balance
31" Series 751 Channel Balance
S751-31
$12.05
How to install a ribbed tilt channel balance with knife lock shoe
How to install a ribbed tilt channel balance with knife lock shoe
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