Hello,
We'd be happy to look into this for you but, unfortunately, the stamp code does not indicate the replacement balances needed for your repair. Your stamp is actually from an outdated weight system, so we will need to know the exact weight of your window sash to determine the corresponding strength option. We will also need to see an undamaged balance removed from your window, including both end attachments, to compare to our inventory. Thank you!
Hello,
It looks like you have either our S351-28, with a 15-002 bottom attachment, or S390-28, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need.
We can't confirm without knowing your exact sash weight but if it is exactly 10 pounds, you'd need 2720 spring strength options for your replacement balances to support between 9-13 lbs. You can find the complete weight chart under the channel balance product descriptions. Thank you!
That's great! Please let us know if you need anything else.