Can you determine the Stamp Option / weight rating from the part number on the balance

Question

I have a 28 4 KJ Caldwell balancer. It is clearly an S390 19" with the 19-002 and 15-001.
Which Stamp Option should I select to match the correct weight?

Thank you
Sam

Tom · Accepted Answer

Hi Sam! There is, unfortunately, no way to accurately determine the stamp option without removing and weighing your window sash. Alternately, the stamp may be printed on your old balance. Can you weigh your sash for us?