Thanks for writing in! The window balances you are searching for are an old, discontinued crossbow channel balance. The good news is that these can most likely be replaced with our Series 795 Channel Balance. Take a look at the video tutorial titled "How to Covert a Crossbow Balance to a Channel Balance" for more information.
To confirm the correct replacement, you'll need to obtain the length of an undamaged balance and you'll need to confirm the exact weight of the sash so that we can determine the correct stamp options for the replacements. You'll also want to measure the diameter of the to confirm that it is 1/2". If it is 3/8" please let me know as these balances will need to be custom assemblies.
These Series 795 Balances will come assembled with a 15-195 1-1/4" T-Lock Shoe with a closed cam. It will also have a screw tab attached to the top, but you'll be able to use the 26-200 Balance Screw Plug along with the 33-016 to install it.