This is an 18K white gold A. Lange & Sohne Lange 1, reference 101.029. It has a leather strap with an 18K white gold buckle. There is a scratch-resistant sapphire crystal and a display case back that is secured with six screws. The solid, three-body 38.5mm diameter case, straight lugs, and rounded bezel are polished. The dial is black with an off-centered time dial at 9 o’clock, and a small seconds subsidiary dial at 5 o’clock. There are applied white gold Roman numerals at the quarter hours, luminous white alpha hands, and diamond-shaped hour index markers. The patented big date double window is at the 2 o’clock position, and there is an up/down 3-day power reserve indicator at 3. It has a quick date reset button on the case at 10 o’clock. It’s water resistant to 30meters (100 feet), and the 9.9mm thick case, dial and movement are all signed.

The mechanical manual winding A. Lange & Sohne Lange caliber L901.0 movement is Glashütte 3/4 plate. It’s constructed with 53 jewels, and 9 screwed-in mounted gold châtons. It has a shock absorber mechanism, a straight-line lever escapement, and a monometallic balance that’s adjusted to 5 positions. It includes the patented fan-shaped, hand-engraved balance cock with a horseshoe-shaped precision whiplash index adjuster. There is a self-compensating flat balance spring, a hand-engraved balance bridge, and a swan-neck micrometer regulator.

This A. Lange & Sohne Lange 1, reference 101.029, is named after the company’s patriarch, Ferdinand Adolph Lange who founded the company in 1845.