Thanks for posting. These look like balances from a very old Pan Am window. We can replace them, but they have to be custom made due to their unique design. Looks like you have 19" balance channels with a stamp code of 1810, meaning they can support a window sash in the weight range of 5 through 8 pounds. Now, these balances will have a 19-035 Top fitting attached. The bottom shoe, the 15-007, is a little weird with this set up. Its such an old design that we can't rivet it tot he metal channel like we do the top fitting. Instead, you'll need to buy the 15-007 separately, along with a 33-073 screw or something similar. You'll then have to slide the shoe into the window track, then screw the shoe to the balance channel manually.
If this all makes sense to you, just tell me how many balances you need, and I'll send you a quote for the balances, stamped 1810, with the 19-035 Top fitting attached. Many thanks.