window coil balance

Hello there. That stamp is good to know, because it tells us the weight this individual coil can support (5 pounds). But it doesn't tell us the coil balance's identity, or what we call its Series. Now the two 'punch hole' tongue design reminds me of our Series 180 Coil balances, but these springs are 15/32" wide; it's admittedly a bit tough to tell from photos of measuring tape, but your coil spring looks to be a bit less thick than that. Can you show us the pivot shoe that connects with this coil balance? The identity of the pivot shoe tells us the identity of the coil balances. That should narrow things down.