When introduced in 1988, the Ingenieur Chronograph was advertised as the world's smallest chronograph. Remaining only for a short period part of IWC's collection, it already had disappeared from the catalogues at IWC 125 years jubilee in 1993. Based on the successful Genta design and originally classified as unisex watch, the Ingenieur Chronograph with its small diameter of only 30 mm today mainly appeals to women who look for a medium sized and elegant sportswatch. This qualities may be the reason why IWC named it as one of the ancestors for the new unisex ref. 4515.

The Ingenieur Chronograph was equipped with the calibre 631, a meca-quartz movement which belongs to the calibre 630 family and was produced by Jaeger-Le Coultre for IWC. These hybrid calibres combine two quartz-controlled stepping motors with a mechanically driven chronograph and belong to the most interesting electronic movements seen in the eighties and nineties.

Specifications:

• meca-quarz calibre 631 with date display and mechanical chronograph
  • produced by JLC (Jaeger-Le Coultre) according to specifications given by IWC
  • diameter: 23.30 mm
  • movement height: 3.8 mm
  • number of jewels: 25
  • frequency: 32,768 Hz
  • movement consisting of two separate step motors with 233 mechanical parts
  • total production: n/a
• tripartite, screwed case
  • water resistant to 3 atm
  • top part with bezel: flat surface with 5 recesses (for screwing tools) in stochastical position
  • without amagnetic soft iron inner cage
  • glass: sapphire
• control of chrongraph functions by push buttons at 2 and 4 o'clock
• totaliser for 30 minutes at 9 o'clock and for 12 hours at 3 o'clock
• small second at 6 o'clock
• date window between 4 and 5 o'clock
• straps and bracelets (bracelets of type «Ingenieur SL» II with raised interlinks)
  • leather
  • stainless steel
  • Mixte (stainless steel/14 ct. yellow gold)
  • 18 ct. yellow gold