I purchased these on Amazon and thought I'd just got a bad unit because we couldn't set the traps.  My landscaper attempted as well and failed.  I then purchased one at the big chain hardware store thinking it was just a faulty unit we'd received.  Nope.  Both were same design and couldn't be set.  I had an older mole trap, same style, that was very sturdy and tough to set, but not impossible.  Wish the older trap was still available.