Will need 12. Top and bottom.
Hello!
Thank you for reaching out to us. This old-style balance isn't made anymore but we can still help. Is the spring diameter 1/2"? I recommend confirming to be safe. If it is, the video tutorial below will show you how to convert to our Series 795.
You'll need the 15-195 shoe which comes attached with the Series 795 by default. You'll just need to measure an undamaged balance as shown in the video to determine the length. The pivot bar will also need to be removed from the sash to see if the 26-366 or 26-021 is the better match.
In that case, you'd want the S795-22 and S795-24 since we round down for the length. There's a chart under the product description that will tell you what stamp is best based on the weight of the window sash.
You can place an order for these balances and the pivot bars directly on our website at your convenience!
No problem. Please let us know if you need anything else and good luck with the repair!