Help finding 16" long Chanel Balance

First step, I need you to re-measure your metal channel. Don't measure the plastic bits, just the metal. It looks to me as if your balance is stamped "14" which would normally (and this is counter-intuitive) correspond to a 15" balance. Is your balance 15" or 16"? Can you also read that "14" stamp? What does it say?

As for the Series of your balance, it could be either the Series 380 or Series 385. The difference between those two lies in the bottom vinyl shoe. You'll need to measure it as shown below. A 1" shoe indicates that you need an S380-15 (or 16, don't forget to double check the length). If the shoe is 1-3/32" or so, choose an S385-15 or S385-16. The length of the channel will make all the difference once you identify the Series using the shoe.

As Mike said, you need to measure your shoe as shown in the photo above. If the shoe measures 1", you have the S380-15. If it measures 1-3/32", you are dealing with the S385-15. In either case, your stamp option is 1450.