Older aluminum single hung

Question

The top is secured by a single screw but I don't see how or where the lower spiral part connects as they had fallen out with the free end resting on the sill. 5/8" x 29". No identifying markings could be found.
These are older replacement windows. (Central Florida) Aluminum single hung single glazed. Very basic window probably 30 years old or so. Thank you.

User submitted photos of a window balance.

Paul · Accepted Answer

Your balance's spiral connects with a bracket at the bottom of the sash. The bracket in question is likely still installed. As for the balance itself, see our S500-29, I believe this could be a match.