Pivot shoe
Hello,
We'd be happy to help but we would need to see your original spiral balance removed from the window to compare to our inventory. The S600 and S900 are commonly used in tilt windows but note that the housing tube should measure either 5/8" or 3/8" in diameter. You'll also need to confirm if your spiral balance has the same studs at the end of the spiral to connect the balance to the pivot shoe.
I can't be sure but it looks like you may have an old-style pivot shoe that is no longer available. The 15-015 is a similar style but note that the depth measures 17/32" as shown below. If you're sure that your shoe is exactly 1/2", our best option would be the 15-046. Look over both pivot shoes to see if one of them could work for your application. Thank you!
In that case, see the S600-25 blue tip spiral balances. Just let us know if you need anything else.
It was our pleasure!