Adjusted in five positions The watch is timed for accuracy in the positions in which it is most often worn: dial up and down, winding crown up and down, and horizontal.

German silver Special alloy composed of copper and zinc, with a nickel concentration of about 10%. German silver is stronger than brass and has been traditionally used by Lange for the manufacture of plates and bridges. The addition of nickel minimises the oxidation of German silver and thus eliminates the need to electroplate the alloy - it can remain "untreated".

Gold chaton The gold setting of a bearing jewel - in Lange watches, chatons are often secured to the three-quarter plate with two or three screws.

Sapphire crystal Glass made of artificially produced sapphire. It is very hard (9 on the Mohs scale) and scratch-resistant. It ranks just below the diamond in these two respects.

Column wheel Also: ratchet wheel, sometimes pillar wheel. A steel switching wheel that has upright columns. It controls all important switching operations in a chronograph mechanism.

Diamond endstone A balance wheel shaft held in place by means of a diamond counter-bearing, or endstone, was one of the hallmarks of "1A" quality pocket watches made by Lange. In Lange tourbillon watches of the new era, diamond endstones limit the axial "play" of the carriage on both sides.

Escape wheel Together with the lever, it constitutes the escapement. It is the last wheel in the going train.

Screw balance A balance wheel that has adjustable screws and tiny washers along its rim.

Chamfering Also: angling, bevelling. The breaking and polishing of sharp edges on bridges and levers. The inclined surface has the same width along its entire circumference or length.

The manually wound L903.0 calibre is one of the most extraordinary masterpieces ever crafted by the Lange manufactory. It is composed of over 1000 individual components, has 41 synthetic ruby | jewels, and is precision-adjusted in | five positions. Six | gold chatons are secured with screws to the untreated | German silver plates and bridges. The | sapphire-crystal back showcases the tourbillon, the chronograph/rattrapante mechanism, and - below it - the | fusée-and-chain transmission. The escapement system of the TOURBOGRAPH - the balance, the | pallet lever and the | escape wheel - is suspended inside a delicate cage that rotates about its axis once a minute. It is precision-balanced with poising weights and its "shake" or axial play is limited at both ends by two | diamond endstones. The | screw balance is shock-proofed on both sides. The terminal curve of the hairspring is bent according to calculations of Professor Strasser of Glashütte, assuring that the balance wheel oscillates isochronously. As is typical for Lange, the chronograph rattrapante mechanism is controlled by two | column wheels. The finishing touches with which the countless movement parts are endowed is nothing short of breathtaking. All edges are | chamfered and polished. Even surfaces that cannot be seen are | circular-grained to perfection or meticulously decorated with beautiful patterns. The finishing processes of the tourbillon bridge alone take two days to complete.