I have been a licensed trapper for several years now and this is one of the tools I use--the 110 Conibear. Now I don't run a trap-line on a regular basis but I have used my license and skills a few times to help friends and neighbors remove nuisance animals and, of course, I've removed my own nuisance animals from time to time.
The 110 is probably my favorite of the conibears and would be my first choice were I to have one available to me during a survival situation. The 110 is good for catching squirrels, muskrats, and rabbits and, used creatively, could probably be used for wild turkey (this is wildly illegal but in a survival situation it's no holds barred FYI.)
The 110 measures 4.5" by 4.5" and uses a single spring to power the trap closed. This is more than enough to quickly dispatch your prey. Having been caught by a few 110s in my day I can attest to the power of that single spring. It's not enough to break bones (in my case anyway) but it'll leave you longing for simpler days when a rat trap snapping down was the biggest of your worries.
The trap pictured above is unset and completely safe to carry. This trap is now set and ready to fire.
To set the trap, you squeeze the spring, rotate the jaws together, and set the dog (the notched piece of metal) onto the trigger (with the long wire uprights) on the opposite jaw. At this point you're in business and your trap is ready to fire.
When you're ready to set the conibear you will need to stabilize it to prevent it from falling over. I like to use sticks picked up from the area where you're setting up and cross them like an "X" over the top of the trap with the bottom legs of the "X" going through the gap between the upright jaws. (Once you've seen a set 110 you'll understand precisely where supports will go to allow the trap to function.)
You can bend the trigger wires to cover more or less area inside the trap to accommodate those tricky animals that can go through your trap without setting it off. I tend to leave mine alone for the most part because I can usually set up my supports and camouflage to force the animal through the trigger.
There is a skunk terrorizing the neighborhood dogs lately and, being declared a nuisance animal by the state, they're fair game any time and any method but I'm going to leave him/her well enough alone unless it becomes a problem for my family or if the folks in the neighborhood ask for my help.
Thanks for reading,