Balance cock Small metal plate screwed to the visible side of the movement. It carries the balance wheel shaft bearing.

Guilloching Engraved ornaments and patterns composed of straight and curved intersecting lines.

Outsize date display Depending on the size of the watch, this useful function makes it possible to display the date up to five times larger than in a conventional watch of similar dimensions. It is based on the patented two-disc mechanism.

Power-reserve indicator The power-reserve indicator displays the state of wind of the mainspring. It reminds the owner that the movement must be rewound again before it stops. Often called "UP-and-DOWN display" by Lange.

Twin mainspring barrels Two barrels in tandem. Lange's twin mainspring barrels allow the implementation of a progressive power-reserve indication and deliver a power reserve of at least three days.

Its name alone emphases that the LANGE 1A is a timepiece of extraordinary quality. The historic pocket watches made by "A. Lange & Söhne" were designated "1A" to indicate that they embody the ultimate in craftsmanship and incorporate the finest and most precious materials available. The unusual going train of the LANGE 1A merits a closer look: True to the tradition of the 1A quality hallmark and as compelling evidence of superb workmanship down to the very last detail, this watch is fitted with a gold escape lever and escape wheel. For both of these components, Lange uses specially hardened white gold because it is much more wear-resistant than yellow gold. The pallet cock, the escape wheel cock, and the | balance cock are also made of gold and individually engraved by hand. The LANGE 1A was issued in a limited edition of 100 watches in yellow gold with a intricately | guilloched dial made of 18-carat gold, an | outsize date, | twin mainspring barrels, and a | power-reserve indicator. It was introduced to commemorate the inauguration of the second Lange manufactory building in 1998 and was produced until 1999.