Andersen Windows Spring unit

Good day.

I have several windows with these spring units, I was hoping to identify a replacement as most have at least one broken string. Each spring has the ID "F3 12 31 1 171" stamped on it, though the 12 31 part in the middle is bigger. Do you have a replacement spring unit for these?

Thank you.
Dan

One more file, this time with dimensions. 2 7/8" x 6 1/4".