I have been looking for a good carabiner for my keys, I have nearly dropped my keys in a river while hiking, lost them once exiting a forklift, using cheap carabiners that do not lock. This one locks, and is heavy duty ! The thing that I like a lot is that it has a separate ring that isolates the key ring from the main opening.
I have the other unlocking Nite Ize, but once I saw a key hit the ground, I went with the locking version. It works great and you will not be sorry going with this one.