What balance should I order?

A home owner from Baltimore says:
August 25, 2018
Hello please see attached pictures and if possible reccomend what I should order to replace my broken windows.
Profile picture of Paul
Paul from SWISCO responded:
August 29, 2018

I recognize this balance that's used for the old Rollyson window. You should be able to use our S371-31 channel balance. Look and see if you agree. Go with the 3030 option to accommodate your stamping of "30C". This will hold a sash weight of 16-23 pounds. 
31" Series 371 Channel Balance
31" Series 371 Channel Balance
S371-31
$11.52
Top Sash Guide Pair, Rollyson
Top Sash Guide Pair, Rollyson
18-124P
$3.92
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