Lauren from SWISCO responded:
October 11, 2021
Hello, It looks like you have either our S351-36, with a 15-002 bottom attachment, or S390-36, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. Comparison of the S351 and S390 balance shoes.
The stamp on your balance is an older version. To determine the strength needed, you will need to get the weight of the window sash and compare to the chart on the product page. Please let me know if you have any questions. |