The A. Lange & Sohne Lange 1 Tourbillon Perpetual Calendar - Limited edition of 100 examples world wide in platinum. The case in platinum is a pleasure to behold, as is the beautifully laid-out silver dial, which still manages to incorporate all the complications and yet still come across as so legible and easy to read. The Lange 1 Tourbillon Perpetual Calendar is a totally new interpretation of the classic complication of the perpetual calendar: never before have the peripheral month ring, the sampling mechanism for the durations of the months, and the instantaneously advancing displays been implemented in a watch this way. The exact workings of the second refined complication can only be observed through the sapphire-crystal caseback on the reverse of the watch: the Tourbillon. The watch features a black hand-sewn alligator leather strap with a deployant buckle.