Pocket knives have been around for centuries.

Pocket knives come in handy during an emergency and have a wide variety of uses.  They can be used to open letters or packages, peel fruit, for personal protection, and all sorts of other things.

I discovered a new use for pocket knives.  I was in a gas station bathroom stall and really needed to use the facility.  However, the stall lock was missing, so I jammed my pocket knife into the lock bracket.  It worked great and I was able to finish my business.

I was saved by a pocket knife.