window balance rods

Hello there. This might be the S377-30, which has a metal channel length of 30" (the end attachments are not included in this measurement), and which uses the 19-018 top fitting. I'm not entirely sure this is what you have, however, so a few extra pictures of that top fitting, and confirming whether or not the diagram below matches what you have, would be good to know. If this does not seem right, we likely still can help, but it may be a balance that has a custom configuration. We'll worry about that later--first, let's see whether or not your balance's top fitting matches what's shown below.

Alternate view of 19-018

Great! I'm glad it's a match. In that case our S377-30 would be my top recommendation.

Please feel free to reach out if you had any other questions.