Searching for 37 9 40# al Caldwell

Thanks for posting. I can't identify this balance without seeing the nylon attachments at either end of the metal channel. The characteristic nylon attachments tell you what balance Series you have. If you could show us pictures of the nylon attachments, that would be most helpful. Finally, once you know what balance you need, you must choose a stamp option. Your stamp code of 37 9 is from an older rating system we do not use. You will need to weigh your window sash. We can that match that precise weight with the stamp option you need. Thanks.