Window balancer that is broken

Hello, thank you for posting, 

Unfortunately I am not able to make out the number stamped on the balance. Is the number on the other balance in the window more visible? 

We will also need to see a clearer image of the bottom nylon attachment. Please also confirm the length of the metal channel excluding the nylon attachments. From there we can move forward with identifying the correct replacement option. Thank you! 

Thank you for the additional images, 

It appears you have either the Series 351, with a 15-002 bottom attachment, or Series 390, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. 

Unfortunately the stamp number is not legible. To determine the strength of the spring needed to support the window sash, you will need to weigh the window sash on a bathroom scale and compare to the strength chart on the series product page. You will need a 29 inch length balance. Let me know if you have any additional questions! 

Comparison of the S351 and S390 balance shoes.

Great! A 28D stamp should translate to a 2840 stamp option that can support a 23-28 pound window sash. We recommend weighing the sash to confirm this range. 

Let me know if you have any additional questions!