Channel is 28 inches long and has 2740P on it.
Thanks for posting. I'm confident we can help, but I'd like to see a version of this balance with the end fittings undamaged. Can you check the other balance from this window, or perhaps an identical window in the house? We'll do our best to assist you from there.
Hello! Bob's not here today, but I can help from here.
The bad news is that your hardware here is just too damaged for us to narrow it down to one recommendation. Your bottom fitting is specifically the problem area. I can guarantee you that this was not flush with the metal channel originally. I can even see evident damage in your photo. No balance was ever made with a flush bottom fitting. There wouldn't be any point to these if that's how they were designed since their function is to keep the balance braced against the sash for stability.
Based on what I see here, you have either our S351-28 or S390-28, depending on the depth of the bottom shoe. That's the only difference between them. Without being able to measure an undamaged version of your shoe, the only thing you can do is guess, which you want to avoid if at all possible. I know that you said that all of your parts are damaged but this really is the only way you're going to figure out what you need, so do your best to get something that is as close to the original condition as possible.
