Caldwell 29 inch window sash balance
A quick learner from Peoria, AZ says:
May 30, 2016
The stamp on the window balance says 28 3 JO CALDWELL. I measured 29 inches and need two of them if you have them. Please let me know.
Tom from SWISCO responded:
June 1, 2016
Hey, Mike. Check out our S390-29. This might be a good match, just make sure your dimensions are the same as ours.