Window channel balance. The only number on unit is 28B USB

It indeed is a funny world we live in especially a funny hardware world with all of these different stamped numbers and markings that unfortunately do not tell us what type of balance we need based off of those markings. Let's see if we can make this funny world work for us to get you what you need. The best way to go about this would be to send us some photos of the entire balance removed from the window. Once we look into this balance, we can provide more information on a replacement.