The ref. IW3725-01 Ingenieur Chronograph has a stainless steel case and matching bracelet. It is powered by caliber 79350 and was in the collection from 2005 to 2008.
Caliber 79350 is the successor to the 79240, which it replaced around 2007. The finishing is slightly different; other than that the movements are identical. Based on the Valjoux 7750, IWC's 79350 is a highly reliable workhorse. In comparison to its base, it dropped the small seconds scale, date and day window. It is produced to IWC's exceedingly high standards and only a small portion of the standard 7750 parts are used.