While the IWC Ingenieur can trace its origins as far back as 1955, the collection was revamped in a rather significant manner in the 1970s following the popularisation of stainless steel luxury sports watches. Designed by Gerald Genta himself, the new Ingenieur SL was a slim ‘Jumbo-sized’ case much like Genta’s Royal Oak that featured an integrated bracelet. Furthermore, it even featured a bezel with four rivets, much like the Royal Oak’s exposed screws. Eventually, following a period of insufficient sales, IWC decided to launch a smaller variant of the Ingenieur, the ref. 3506, in the mid-80s, which is what we have here. With an emphasis on IWC’s elegant design language, the ref. 3506 utilized design touches such as gold hour markers and hands along with slightly textured dials in a bid to swap the Ingenieur’s tool-watch design with a sophisticated look that echoed IWC's dress watch aesthetic while remaining true to the new Ingenieur. Produced only for a short period of time, the ref. 3506 was well-received while it was in production, and today is a rare variant of the Ingenieur that collectors still love to see.

The watch is in overall excellent condition. It exhibits minor signs of wear on the case, including a few small superficial scratches. The original dial with tritium indexes is in excellent condition. Watch was serviced in 2017 by IWC in Schaffhausen and had its hands replaced with service luminova ones. The bracelet has 23 links, 5 of which are removable.

Another one of Genta's great designs, the Ingenieur has unfortunately been updated yet again by IWC making vintage pieces like this ref. 3506 all the rarer and more important for collectors to cherish. Due to its timeless aesthetic, this ref. 3506 could easily be strapped onto a wrist and worn right away, as is Genta's design's staying power.