A little work in progress, this 'shellter' was designed after hearing hermit crabs inhabiting shotgun shells. So I thought that, the best way to make an artificial shell, is to make something that we already know hermit crabs inhabit that is man made, and thus the "Shotgun Shellter" was born. With the little ridges I find in most shotguns, the metal 'lip' on the back, but added a slight curve so it would easily conform to the cuved abdomen of the crab. At the moment the object itself is very small and needs to be resized for the hermit crab in question, but you probably need to resize it for your particular hermit crab anyway.Future Designs- Probably going to introduce a few different variations, including one with a "D" shaped opening and a few that are thinner, longer, have a sharper curve.