Movement
Inside ticks a Sellita movement, a caliber SW200, which is in fact exactly the same as an ETA 2824. When the Swatch group announced they wouldn’t deliver ETA movements to non Swatch Group brands, several watch brands started to develop their own movements. These newly developed movements were mainly chronograph movements, and there are no real substitutes for the basic, but extremely useful, ETA 2824 and ETA 2892 calibers.
That was a task that Sellita, Soprod and several other (new) movement suppliers took upon themselves. These movement suppliers made the necessary ETA clones and now we see brands like IWC (and others) who start using these ETA clones. The movements have more or less the same specifications, so parts can be exchanged with ETA parts. Not that there’s an urgent need for that, however since parts like the stem are also interchangeable, it these new parts can also be used for servicing watches with an ETA movement.
http://www.monochrome-watches.com/iwc-ingenieur-automatic-ref-3239-reviewed/