Replacing balance on Great Lakes (Plygem) window

Hello there! Thank you for reaching out to us. Your balance assembly resembles the Series 770. Your stamp is odd though so you will have to weigh the window sash on a scale to determine the proper option for your replacements. There's a chart under the product description on the S770-24 store page that you can use as a reference. 

As for the pivot shoe, the 15-129, 15-135, 15-152, 15-167, and 15-179 come to mind. Carefully review the dimensions and see if one matches up to your old pivot shoe. 

23HD isn't a stamp option that we offer for this Series of balance. On the S770-24 store page, you will see a list of options such as: 

• 24B
• 24C
• 24D
• 24E
• 24F

Each of these stamp options is calibrated to support a certain sash weight range. It could be that your stamp is from an outdated rating system. With that said, weighing the window sash is the only way to pick the accordant stamp option.