This is the famous White’s Auto Fisher AKA the YoYo survival fishing reel. An absolutely brilliant self hooking item. Set them up, go create your camp, light a fire and relax. Come back later and there is your dinner. Simple. Of course you need the right bait, and there needs to be fish, however assuming both then with a few of them out you are never going to go hungry.
One is not enough, selling in the original 12 pack. There is nothing more disappointing than having NO dinner.