How to read stamp on balance spring

A quick learner from California says:
How do I know what stamp option I need? The old spring has "26 5 LU CMC 1" stamped on it. It is a 1/2" channel, 27" long spring. Thanks!
Profile picture of Tom
Tom from SWISCO responded:
Thanks for posting! A stamp of 26 5 usually corresponds to our 2650 option. Does the weight of your sash match the rating shown for the 2650?
A quick learner from California says:
No. The sash is only 21 lbs. I went ahead with the lower weight one rather than the 2650. Thank you!
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)