I carry a small wire saw that has proven itself more then once for everything from making a shelter to cutting fire wood. The multi-tool has "locking" jaws like a pair of Vice-Grips, a lock blade knife that is on the outside of the frame so you don't have to open the tool to use it, wire cutters, a file, a saw blade that will cut metal, a bottle/can opener, and both philips and flat blade screw drivers. The little knife started life as a replacement blade for a utility knife. I will post an instructable on how I made it in the near future.