Verify Channel Balance

Thanks for posting. I can't tell if the Series 380 is a match or not. It really depends on the style and size of the nylon caps, and I can't make them out from your picture. As long as they match the 19-005 and 15-005 though then you should be okay.

As for the option, you usually want to go by the stamp on your old balance. If you don't think the old stamp is accurate though, then I recommend weighing your sash on a scale and referring to the chart on the S380-13 store page. It's not always a good idea to go heavier, since it is totally possible to have a balance that is too strong. If it's too strong, you'll find it difficult to close the window. In some cases, the window will even drift up after it's closed.