Window balancer replacement part inquiry

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. When we measure the length of channel balances, we measure the metal channel, not including the end attachments. 

Take a look at the image below to determine which balance you'll need. You'll also need a 2730 spring strength option for your replacement balances. Thank you!

Comparison of the S351 and S390 balance shoes.