measured metal length 27 inches

With this combination of attachments, you could have either a Series 380 or Series 385 channel balance. You need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. It looks like you'll need the S385-35. You'll also need a 2630 option on the balance that you choose based on your stamp number. 

Thank you and let us know if you have any other questions or concerns.

Comparison of 15-004 and 15-005