I was in Lansing IA for fish days and stopped in the commercial fishing museum and saw this trap.I’m not sure the type of set it would be used at or critter it would catch but it obviously didn’t work real good or they would still be in production.

That's a fascinating thing, Mad Scientist. Thanks for showing us.

Appears to be a one way entry trap. I wonder if it was designed for use in a blue bucket cubby set?

I was thinking a hole thru the ice.Set the trap upside down with bottom flush under the ice.Would only work on warm nights so hole doesn’t freeze.Would be fun to own one and figure it out.

I think the trap was meant to set flat on the bottom of the water. Might be a fish trap but sure looks like a beaver trap to me. You place bait stick on trigger lower to bottom and beaver finds it.