Aluminium Window Balance Replacement

A contractor from Atlanta says:
I need to order two different block and tackle glances for a few windows. Here is what I can find on the parts:

First set: Lettering on the unit 30 9 BR CAELDWELL, Length 31", Width 1/2 " see pictures attached. I need four of them

Second set: Lettering on the back 20 E 15, Length 29", Width 1/2" see pictures attached. I need four of them.

Can you help please.
User submitted photos of window balances.
Profile picture of Paul
Paul from SWISCO responded:
Looks like you have two different Series channel balances. Fortunately, they're both standard. Take a look at our S385-31, which comes with a 19-005 top attachment and 15-004 bottom attachment, and our S390-21, which comes with a 19-002 top attachment and 15-001 bottom attachment. Just make sure that the size of all the attachments I mentioned match your own before you make a decision. You will also need to weigh each sash in order to determine the appropriate stamp option.
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