IMO, DCMatt is correct. The main ID-clue is the object being "hinged" -- so it could be folded over flat against the clock's back instead of always sticking straight out from the back of the (portable) alarm-clock. I recognize it because my grandmother (1888-1980) had a clock like that in her house, and sometimes she would ask me to wind it.
BTW, I was agreeing with the gas valve key ID until the finder (later) mentioned that "It’s hinged where it attaches to the round part."
Another BTW, as a follow-up to the story about my grandmother:
I've found that surprisingly often, showing a "mystery object" you've found to several very elderly people will result in a correct ID... because they recognize the object from seeing it and using it when they were young, 50 to 80 years ago. So try asking your grannie and grampa and your elderly neighbors.