The Lange 1 Time Zone was introduced into the market in 2005, and features a movement made of untreated German silver and decorated with Glashütte ribbing. The twin mainspring barrels provide a power reserve of three days when fully wound. It furthermore features a stop second mechanism activated when the crown is pulled out and a patented twin-disc mechanism for the display of the oversized date.

The model features two eccentric dials each with its own independent day/night indicator. Using a system which allows easy adjustment, the wearer can select which time zone is to be displayed on the larger of the two dials: home time, or the local time in a particular country, or any other time zone. The second time zone can also be easily selected using a push-button and a rotating city ring. With each push, the city ring and the hands of the second time zone advance simultaneously one notch and one hour. The oversized date is automatically synchronized with the larger of the two dials.