This light, well-made  Swiss+Tech MMCSSS Micro-Max 19-in-1 Keychain Multitool can be extremely helpful. The Swiss made solid stainless steel tool set, with its patented, quick release and self locking mechanism, folds out into 19 different professional-tools.

2 hex wrenches, 6 screwdrivers, pliers, wire cutter, wire stripper, wire crimper, hand drill, file, bottle opener, 2 rulers (mm and inch), plus 2 ruler extensions. The folding design of this tech gadget also allows this to be carried in pant pockets. Pretty handy, huh?