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 sophisticated complication of this watch can be observed through the sapphire-crystal caseback on the reverse of the watch: the tourbillon.

	Model in platinum Reference 720.025. Edition: 100 in platinum. Movement: Calibre L082.1. Self-winding mechanism. Tourbillon with patented stop seconds. Perpetual calendar with outsize date, retrograde day-of-week display, month ring, and leap-year display. Moon-phase display. Day/night indicator. 50 hours power reserve. Dial: Solid silver, rhodié. Hands: Rhodiumed gold. Case: Diameter 41.9 mm. Height 12.2 mm. Sapphire-crystal glass and caseback. Hand-stitched crocodile strap.