My wifes grandpa has a new house no 3 1/2 of unknown value. Hopefully someone on here can tell me its approximate value. I has a dual spring on one side and teeth. Chain, swivel and teeth all seem to be in original condition.

You provide enough details for an estimate but first. this trap should have just one spring. The spring on the off chain end (the end of the trap without a jaw post) was not original and will need be removed to make the trap fully collectible. and it appears that there is an added spring on the chain end as well. Once the extra springs have been removed, if the original spring on the jaw post end of the trap is strong and can be used the remainder of the trap appears to be in decent collectible condition with teeth, pan stamp that might be a large Canadian stamp full chain and ring and overall nice appearance and should bring 150.00 or perhaps considerably more. Canadian collector lots of mink on here will be a close excellent reference person

Very cool

That dual spring is my biggest question. Is it possible it's a very rare trap and the second spring is OEM,? It seems like a lot of work to put on, and it makes the trap impossible to set by hand like normal

Like say for instance its like a mistake in the factory. Like a miss struck coin?

Super Neat Looking Trap anyways!

Not a mistake, just trapper mods which are very common