Indoor,
I think you might be viewing this amazing and innovative product all wrong. Cheaper Than Dirt has the image upside down.
This could actually be one of the most useful add-on tools ever conceived.
Think about it: You find yourself stranded in the deep woods. Far from home, completely alone, and with nothing but your wits and a small pocketknife. BUT, thanks to your forethought to purchase this ingenious tool, when your pocket knife won't cut it, BAM! You flip it over and there is your back-up mounted North American Arms revolver!
It's genius really and we all need to think about adding this useful tool to our duty knives.
What the heck is that mounted on....a derringer?