Swiss Army Knife Reamer
The reamer tool on the Swiss Army knife is designed to make or enlarge holes in materials like leather, thin wood, cardboard and thin plastics. You simply insert the point into an existing hole or push it to create a new hole and then turn it. It works really well.
The reamer tool also has a small eyelet hole which enables it to be used as a sewing needle. You can thread a piece of twine through the hole and then use the reamer as a needle and thread. You can fasten or sew 2 pieces of leather together or fix a torn leather shoe.