Looks like a spring balance

Question

There are no markings. They are springs inside a plastic cover. About 27 inches from where it is attached to the side of the window to the top of the sliding window top.  The plastic is gone on some windows and the spring is curling.

Tom · Accepted Answer

Thanks for reaching out to us! Looks like you need a new spiral balance. We sell quite a wide selection of different kinds, but your window here appears to be an older, non-tilt style. My concern is that it may be a little too old for us to be able to help with; these are far from popular these days and replacement parts are getting harder to come by.

To confirm, would it be possible to see a picture of the very bottom end of the spiral rod? This would be where it connects to the sash at its bottom corners. If I can see that, I can tell you for sure whether this is something we can still supply.