German Door Latch Sicherheit Riegel
German door latch Sicherheit Riegel ("safety latch"). This is likely from a train car or a bathroom or something similar. It latches from one side and has no way to unlock it from the other.
This looks more modern, but some of the cast aluminum items from the thirties have a surprisingly modern appearance and design so it may very well be older.
It is in usable condition with a small crack near one of the screw holes. The crown casting mark also seems older to me. It is a little bit outside our expertise but we couldn't leave it behind. It measures about 6 1/2" by 1 3/4".