Channel tilt balances for plain channel Imperial window

A quick learner from San francisco says:
Hi I need two 29 inch plain channel Series 770 channel tilt balances. However I don't know the stamped option The frame says 29s 3 si 34 EE

Can you figure out what I need from those numbers!?

Thank you
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Jasmine from SWISCO responded:

Thanks for posting! To determine the stamp, it would be best to obtain the exact weight of your sash. You'll then use window weight to chose your stamp based on the weight ranges listed on the chart below the product description for the S770-29.

I hope this helps!

How to replace a tilt-window channel balance.
How to replace a tilt-window channel balance.
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