Behrens BHR030 Inventor Ultra-light 20g

Behrens built the Inventor Ultra-light around a specific constraint: 20 grams total weight. Everything else — the open-worked titanium case, the skeletonised dial, the visible movement architecture — follows from that decision. What you hold barely registers on the wrist, yet contains a complete in-house automatic movement visible in its entirety. This is the kind of engineering that impresses people who understand engineering and mystifies everyone else. Full box and papers.