The case itself takes elements from both the ref A386 and ref A78x family. It is still somewhat tonneau shaped, but is a lot more angular than the ref A78x (the A3817 actually has visible lugs, for instance). The edges on the case are distinct and sharp, similar to the ref A386. The surface of the steel case also has a brushed finish, which lends it an interesting look.
The case design was an unexpected, but pleasant surprise. It departs from a ‘typical’ case design (such as in the A386), which usually has a circular and symmetric center that envelops the dial. At the same time, it is not too funky, in comparison to the case design of the ref A781/2/3 family. I used to own a ref A783 – now that was a chunky watch. It felt like I was wearing a block of metal on my wrist, and as a result that watch never really got much wrist time despite the amazing El Primero movement that beat inside. The ref A3817 is a nice balance between the two: innovative, different, but still sleek; retaining a classic elegance with a dash of eccentricity.