The kit, as explained in detail here, addresses five core survival needs: water, fire, shelter, signaling, food. Beyond the obvious benefits of having a shotgun for hunting, shotguns typically have a lot of unused space to provide cushion for the kickback and can use special shells that act as signal flares. They mounted a knife, flashlight, various shells, parachute cord (that can be disassembled into several strands), a saw blade, bandana and compass on the outside. In the unused spaces they were able to fit a multi-tool, fire starter kits, and a rather comprehensive survival kit (containing items such as a fishing kit, aluminum baking-pan, water purification tablets, first aid basics, and a survival blanket). They claim it is the ultimate kit for a zombie apocalypse, however I can see a lot of benefits for more practical uses like getting stranded in the mountains.
