Please help identify this window balance

Hello,

Your balance looks like our S350-23 channel balance. You'll also need a 2230 spring strength option based on your 22 C stamp. Take a look and let us know if you need anything else. Thank you!

A lot of older balance manufacturers used to use letter codes to indicate spring calibration. Over the years, more modern manufacturers switched over to a numeric system. It's a 1:1 reference. A is the same as 10, B is the same as 20, and in your case, C is the same as 30. You can always weigh your sash on a scale and refer to the chart on the S350-23 store page to be 100% sure. I always recommend doing that anyway. You can never be too certain.