Hello, thank you for posting,
It appears that your window uses an older rod balance that is no longer made. We recommend reviewing the Series 770 channel balance as an updated replacement. You will need to measure the length of the balance and obtain the weight of the window sash.
Compare the weight to the strength chart on the S770 product page under the length needed to confirm the correct spring strength stamp option needed to support the window sash.
The new balance will be compatible with your current pivot shoe. If you need a replacement, start by reviewing the style and dimensions of the 15-135. The original will need to be removed for accurate dimensions. Let us know if you have any additional questions!
