Replacement window balance

Thanks for reaching out! Your balances appear to the be the S770-27 channel balance with both a 27C and 27D stamp. If these balances were removed from the same window, you'll need to confirm the exact weight of the window to determine the exact stamp you'll need.

The 27C stamp is made for sashes weighing 17 to 22lbs, the 27D stamp is made for sashes weighing 22 to 26lbs. Once you have the exact weight you'll need to confirm if it is just under 22lbs (for example: 21.8lbs) in which case, I would recommend the 27C stamp. If the weight is over 22lbs and over, I recommend the 27D stamp.

You'll want to have balances with the same amount of tension in the window so that one is not worn out faster than the other.

Let me know if you have any questions.