Window balacers
This is an old rod-type balance that hasn't been made in many years now. The good news is that you can use one of our modern channel balances to replace it, but it takes a little handiwork.
To start, can you verify that the diameter of the spring is 1/2"? If so, you can use our Series 795. The video below will cover the entire conversion process step by step, but I'm happy to answer any follow up questions you may have.
Note that if your spring is 3/8" instead of 1/2" then you have something else. I can help with that, too, just let me know.
Your first picture appears to be of the balance. Could you be referring to the pivot bar? If so, what you show there might be our 26-021. However you should review our dimensions to ensure that they align.