I had one on my key chain with my car keys.
i had it for about a week. i think I opened all of one box with it. It worked well, but one night i put my keys into the ignition, cranked the ignition to start the car, and heard a little "ping" as something hit the floor.
That something was my swiss key. The latch had snapped off, and it can no longer be affixed to a key ring.
it DOES hav a warranty, and I could send it in and get it replaced, but it seems like a LOT of hassle to go through for a novelty item.