2 different Sash Balancers

A handy person from Long Island says:
I'm trying to replace these with new ones. Can you tell me which one to get please? i hope they are all the same because i need 4 of them. Thanks

User submitted image of their window hardware.
Profile picture of Paul
Paul from SWISCO responded:
Hello! These two balances are not the same. Do they go on the same window? If so, that might raise some problems. The first one, which appears to be older, is stamped "837." This corresponds to our 24-837 Andersen sash balance, unsurprisingly.

The second, which looks somewhat newer, is stamped "7#31." This stamp relates to our 24-737 Andersen sash balance.

According to my records, these balances are used on windows of the same height, however the 24-837 window might be somewhat wider, requiring a stronger balance.
How to replace an Andersen Window Balance
How to replace an Andersen Window Balance
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 4-7 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.