This is three genuine American made mainsprings for genuine American pocket watches.
These are special because if you ask anybody it is getting really hard to find pocket watch mainsprings. And, when you find one that works, it's often not exactly right. These 3 springs are:
Hamilton 12s #3328
also for a Hamilton 12s that is .018 in thickness, so that if some standard white alloy mainspring makes your watch overbank (or knock the banking) by using the right mainspring you'll get the amplitude down to a fantastic rate.
Elgin 0s #2097 which is .00575 thick.
Not the one you need? Check our auctions - we have MANY listed