Leatherman
The smallest models can be carried on your key ring. It means you’ll always have (among other things) a knife, scissors and bottle opener with you: so handy! Want more features? The most comprehensive multi-tool has up to 29 tools. Some might say that’s overkill, but if you're a handy DIYer or work as a mechanic, for example, you can put them to good use.
What does such a comprehensive model include? Everything from a can opener to wire stripper, wood saw, pliers, screwdriver, ruler and a diamond file. Most tools fit perfectly in your pocket, but the more elaborate they are, the heavier they are too. You can attach them to your belt with a sturdy pouch. Because nobody likes ripped trouser pockets.
By the way, did you know that the idea for these rock-solid multi-tools was the result of a tour of Europe some forty years ago. Tim Leatherman was on holiday with his wife in a Fiat 500. It broke down regularly, and the pipes in their hotel rooms also leaked more often than they would have liked. When carrying out the repairs, Tim’s pocketknife got him a long way, but he was missing a pair of pliers. He retrospectively designed a multi-tool that is now used all over the world to fix cars and much more. His motto: leave nothing undone!