25 3 ES CALDWELL [Metal part is 26" long]

Thanks for posting. I am certain we can help, but I'd like to clarify one detail. Can you show me the point where the spring and pulley system meet in the 'guts' or underside of the metal channel? We should be able to proceed from there. Many thanks.

Great thank you! 

With this combination of attachments, you could have either an S380 or S385 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. 

You will need a 26" balance with a 2530 stamp option. Please review and let us know if you have any additional questions! 

Comparison of the S378, S380 and S385 balance shoes.

Because your old stamp is 25-3, which typically means the same exact thing. If you have any doubts, I would recommend weighing your sash on a scale to verify that it falls in that weight range.