Need help identifying window channel balance

Thanks for posting! I think you may be a little off. It looks like both your top and bottom nylon attachments have wings on them. The Series 351 attachments do not have wings. With this in mind, I think you should consider instead either our Series 380 or our Series 385 balances.

Now, as you can see, there is only one difference between these two Series, and that is their bottom shoe. The Series 380 uses the 15-005 while the Series 385 uses the 15-004. I can't quite tell what you have based on your pictures, though. Please carefully compare their dimensions to your own hardware and see which is a better match. I also recommend that you double check the length of the balance's metal channel. Based on your stamp, the length should be 27", not 17".

Both the S380-27 and S385-27 have options that can carry a 22 pound sash weight.