Is this a locksmith's tool? plus odd key

[mkz]

Hello,
I bought a collection of old keys and this gadget was included. I have no idea of its purpose or if it is complete. My best guess is some sort of locksmith tool or a part to something. The only mark is "PAT APPL FOR". It measures approx. 1 3/4" long. The little tab will move up and down and located in the end is what looks like a key hole. I am also including photos of another key in the collection that states it was made by Yale for Max Frankel, Syracuse NY. I've not seen a key personalized like this before. Any info about these two items will be greatly appreciated!