This is a large and very fine 36.5mm stainless steel IWC Ingenieur ref. 666 dating to the 1950s and housing the caliber 853 automatic winding movement. The inner soft-iron case protects the watch from magnetic fields (as it was designed to do so). The large steel case with screw-back displays extra-fine condition. The original ivory dial with original gold-toned Dauphine hands and arrow markers looks fabulous. This is a very fine example of a rather uncommon vintage IWC tool watch.