No stamp on balance spring

Question

Hello,

In comparing your our model S385-22 balance spring with my 29 year old one, it sure looks like an excellent match. There are no stamps on the existing balance and the window weighs 12lbs. Should I order an 2120 or 2130 replacement?

Thanks,

Eugene

Bob · Accepted Answer

Hi Eugene. If the window weighs precisely 12 lbs, then go with the 2130. I don't think you can go wrong with either option though.