26 9 34# window springs
A handy person from Seattle, WA says:
June 29, 2016
I need to replace four side springs; Part number 26 9 34# GL Caldwell.
Tom from SWISCO responded:
June 30, 2016
I'm afraid we cannot identify what you have based on the stamp alone. I recommend browsing through our Channel Balance Home Page to find the best match.