A compact wrench which fits in your pocket, and uses interchangeable blades to provide different size openings for a variety of nuts, as well as bicycle spokes. It’s even got a bottle opener blade. Made from stainless steel, and holds up to five blades at a time.
We have seen micro wrenches before but this Pocket Wrench design that comes in at the size of a key may be the smallest. It comes in SAE and Metric, and also works as a ruler, socket driver, screwdriver and, yes, bottle opener.