Window coil balance springs

Question

540 is what is on the coil. I saw no other identifying marks, numbers, words or letters on the parts or the window. All of the stickers on the windows appear to have been worn or taken off.

Emily · Accepted Answer

Hello!

This looks like an older version of our 15-180, which uses Series 190 coil springs. Compare our dimensions to yours to see if this matches up to your original pivot shoe. If your coil spring is stamped "540", see the S190-540.