Short answer

A replica Lange Big Date copies the outsize date window of the A. Lange & Söhne Lange 1. The real watch has a 38.5 mm case, a hand-wound L901.0 movement, and a two-disc date that reads 01 through 31. Copies sell from about $70 to $1,200. No copy uses the L901.0. Listed copy case sizes run from 38 mm to 42 mm. Listed thickness runs from 11 mm and up against 9.8 mm on the real watch.

How the outsize date works

Lange calls the feature Grossdatum. Two discs sit behind one aperture. The tens disc carries 0 through 3. The units disc carries 0 through 9. Each digit prints at a size a single-disc date cannot reach in the same window. Lange filed the patent in 1992. The Lange 1 arrived in 1994.

Real Lange 1 specs

  • Case diameter: 38.5 mm
  • Case thickness: 9.8 mm
  • Movement: L901.0, hand wound, twin mainspring barrels
  • Parts: 365
  • Jewels: 53
  • Power reserve: 72 hours
  • Beat rate: 21,600 vph
  • Dial layout: off-center time dial at left, outsize date at the top right, power reserve at 3 o'clock, small seconds at the bottom right

Copy price tiers

  1. $70 to $200. Quartz or low-grade automatic. Printed date numerals. Mineral glass. Plated case.
  2. $250 to $500. Automatic movement with a decorated cover. Sapphire on some listings.
  3. $600 to $1,200. Sold as a super clone. Sapphire front and back. Fake screws and jewels on the movement cover.

Used real Lange 1 watches in yellow, white, or rose gold list from about $25,000 on the secondary market. Platinum and limited dials run higher.

What to check on a copy

  • Thickness. The real watch is 9.8 mm. Copies sit near 12 mm and above.
  • Date discs. Two discs on the real watch. One disc under a mask on many copies.
  • Numeral height. The tens and units digits should match in size and sit on one line.
  • Date corrector. Lange fits a recessed pusher on the case flank. Some copies use a crown position instead.
  • Movement. Ask for a photo. A rotor on a hand-wound design points to a cover plate.
  • Weight. Gold is denser than plated brass. Ask for a gram figure.

Movement finish gaps

The L901.0 uses a three-quarter plate in untreated German silver, blued screws, and a hand-engraved balance cock. Copy plates are rhodium plated. Engraving on copies comes from a laser. Screws are polished steel. Some jewels are set for looks. A basic copy movement can drift 20 seconds a day or more. Lange adjusts the real movement to a tighter rate.

Legal and shipping facts

US Customs and Border Protection can seize counterfeit watches at the border. The OECD lists watches among the top counterfeit product categories in its trade reports. Selling a copy as a real watch is fraud. Buyers in the US take the import risk on the shipment.