channel balance 27'

Hello, thank you for posting,

It appears you have either our S351-27, with a 15-002 bottom attachment, or S390-27, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. Also review the metal channel for a number stamped that will indicate the stamp option that indicates the strength of the spring needed.

If there is no number present, you will need to obtain the weight of the window sash and compare to the strength chart on the product page to choose the correct stamp option.

Please review and let us know if you have any additional questions. 

Comparison of the S351 and S390 balance shoes.