Window balance

Thanks for posting. This reminds me of the 15-156 Certainteed Spring Cover, which is used with the 15-192 Pivot Shoe and Series 170 and Series 171 Coil Balances. However, the Certainteed design has 'aligners' on the surface of the pivot shoe that other versions of this shoe lack. If you're replacing the pivot shoe and not just the covers and springs, you may need to rub those aligners down in order to get the replacement shoe to fit the window track. Just note that modified items cannot be returned for refunds. 

The video below goes into more detail on the Series 170 and Series 171 Coil Balances and what the difference is between them. Let me know if you have further questions.