Believe it or not, The US Army SERE School highly recommends their students bring a pocket survival kit containing the items below. This is what you are limited to bringing when reporting to SERE School (IN THE POCKET SURVIVAL KIT)

Contents:
BOX OF MATCHES
4 FT OF ALUMINUM FOIL
2 FUEL TABS
50 FT OF FISHING LINE
5 FISHING HOOKS, SWIVEL, & 3 BB SHOT SINKERS
4 SAFETY PINS
20 FT OF GREEN OUTDOOR RATED THREAD
SEWING NEEDLE