Custom Shoe?

Hello,

Your balance resembles the S751-27 channel balance, which uses the 15-014 knife lock shoe. This looks the same as your shoe except for the color, which doesn't indicate that you need a custom part. Look over the balance and shoe to confirm that the specifications match up to yours. 

Note that the rivet used for installation is positioned in the second hole from the top of the S751 balance. I'd also recommend weighing your window sash and following the chart under the S751-27 product description. Thank you!