Replica Jaeger-LeCoultre Ultra Thin watches copy the Master Ultra Thin line. Case sizes run 34 mm to 40 mm. Prices run $150 to $900. The largest gap against the real watch is case thickness. The genuine Master Ultra Thin 1907 measures 4.05 mm front to back. Most replicas measure 8 mm to 11 mm. The movement inside sets that limit.

What the genuine watch carries

Jaeger-LeCoultre builds the Master Ultra Thin around two movements.

  • Caliber 849: hand wound, 1.85 mm thick, 21,600 vph, 35 hours of power reserve, 123 parts.
  • Caliber 896: automatic, about 4 mm thick, 28,800 vph, 43 hours of power reserve.

Cases come in steel, pink gold or white gold. The Master Ultra Thin Moon at 39 mm measures about 10 mm thick from the moon phase module. Sapphire covers the dial and the caseback on both.

Movements found in replicas

Three movement families show up in replica builds.

  1. Miyota 9015. Automatic, 3.9 mm thick, 28,800 vph, 42 hours of power reserve. Common in $250 to $500 builds.
  2. Chinese automatic. 21,600 vph to 28,800 vph. Decoration plates cover rotor screws and jewel settings.
  3. Hand-wound clones. 21,600 vph. These allow thin cases, with a few builds near 6 mm to 7 mm.

Points to check before buying

  • Case thickness. Measure the watch, not the listing. Numbers above 9 mm are common on automatic copies.
  • Dial print. The genuine dial carries "JAEGER-LECOULTRE" under 12 and "AUTOMATIQUE" above 6. Letter height and spacing shift on copies.
  • Date wheel. Font on the genuine wheel is thin and matches the dial print. Copies use a heavier font.
  • Crystal. Real watches use sapphire. Lower tiers use mineral glass, which scratches.
  • Caseback. Genuine engraving is deep and clean. Copies show shallow laser cuts.
  • Weight. Gold plated brass cases weigh less than steel. A 39 mm steel case runs about 60 g to 70 g with a strap.
  • Water resistance. Sellers claim 30 m or 50 m. Gaskets on replicas are not tested. Keep the watch away from water.

Service and parts

A watchmaker can regulate a Miyota 9015 and replace it for $60 to $120. Clone movements have fewer spare parts. Plating on gold tone cases wears at the crown and lugs after one to two years of daily wear. Ask for photos of the caseback and a side profile before payment.