30 inches long, marking 2922DS BJ

With this combination of attachments, you could have either an S380-30 or S385-30 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. You'll also need to weigh your sash to determine which option you'll need. There is a chart on the product page that explains how to choose your option based on the sash weight.  

Thank you and let us know if you have any other questions or concerns.

Comparison of the S378, S380 and S385 balance shoes.

In that case, you should be able to use a 2975 strength option for your replacement balances to support between 42 and 45 lbs.