18"in. Window balance product name UNIQUE stamp 16-B-20

Hey there,

Thanks for posting! Given the stamp from your balance, the length of the metal channel should be 17". When measuring the length, the top and bottom attachments should not be factored into it.

That said, you can need either the S380-17 or the S385-17 to replace your balances. To determine which of these is the right fit, be sure to look over the diagram below for reference.

I believe you can select the 1620 stamp to replace your 16-B stamp; although, it might be a good idea to make sure the sash weight falls between 8 to 12lbs.

Comparison of the S378, S380 and S385 balance shoes.