Window balance Caldwell 29 3 BQ
Thanks for posting! I've gotten the possible balance replacement narrowed down to a few options. To confirm which of them is the best fit for the window, I'll just need to confirm a few details.
To start, please provide a photo of the bracket that connects the spring and the string in the center of the balance. I'll also need to know the measurement for the depth of the shoe (front to back).
Based on a search of the archives, it looks like I need the 395 series.
This balance has a winged top guide and a winged bottom shoe, whereas the Series 395 has a wingless shoe. That said, you'll need the S385-30 to replace your balances.
You can likely use the 2930 stamp option; although, it would be a good idea to double check that your shash weighs between 16 to 23lbs.