The Richard Lange Pour le Mérite is by far my favorite offering because of the tremendous tour de force technology behind it.
The chain and fusee transmission is a simple concept as it spreads torque very evenly across the chain. However, when it was first introduced some 200 years ago, because of crafting technology, it was not feasible to produce such small precision components at the time. Today, thanks to sophisticated machinery, Lange has revisited a good but previously unfeasible idea that has been dormant for nearly 200 years. This really furthers Lange's motto of "State of the Art Tradition."