Field shovels accompany soldiers for decades. Their advantage is that they are folding, therefore space saving. You can use them for digging but in emergency cases for cutting as well. They could of course be used for selfdefence as well.
Besides the military use they could come handy in civil life too. Many people have experienced a situation when they mired with the car. Small folding field shovel does not take much space in the car, however, it makes a lot of work. Do you already have it?