Replacement balance cylinders for 2021 sierra pacific double hung window

Thanks for writing in! Your balances remind me of the Series 751 Channel Balance with a 15-014 knife lock shoe. Specifically, you'll need the S751-28.

Unfortunately, I am unable to cross-reference the stamp from your balance to determine the stamp option you'll need. With that said, you'll need to obtain the exact weight of the sash. 

There is a chart below the product description of the S751-28 balance that lists the weight ranges each stamp option can support. If yours does not fall between any of the listed weight ranges, this will need to be a custom assembly. 

Please let me know if you have any questions.