Anderson balance 11 600 17?

Thanks for posting. I am afraid we can't pinpoint what sash balance you need from this stamp alone. Elsewhere on the balance box there will be a certain stamp that should tell us what it is. We'll need you to remove the balance box and photograph all the stamps on it. Send us the pictures of the stamps and we should be able to narrow it down from there. See the guide below for details. 

Guide: Andersen's Narroline Sash Balances

Thanks, this will do just fine. See the 24-1033. This will replace old Andersen balances with that '1027' stamp. It is nonhanded and will work on both sides of a window.