The 14mm height is reasonably shirt-friendly

The simple caseback shows the other design feature I dislike - the quick-release strap and bracelet system. Unlike almost every other watch out there, the Aquatimer series use a lever-release system that IWC licensed from Cartier. It's really cool, requiring just the tip of a finger to release, but since it's proprietary the only place in the world outside of IWC that makes straps is the very expensive ABP of Paris. Having emailed ABP, their least expensive strap to fit would start at 250 Euros... wow. That's still much cheaper than IWC, though, who want $360 for a Velcro strap, $400 for the rubber and a rumored $1500 for the bracelet! IWC has done proprietary lugs since the iconic 3536 diver, though the design has changed with each generation, so it obviously makes sense to them. So while the system works well and is certainly convenient, it does make purchasing your own straps, or replacements straps and bracelets very expensive.

It's a nice rubber strap and buckle, but $400? I've got the Velcro on order, from what I can tell it allows the use of normal 19mm straps, and am keeping an eye out for a used bracelet. It's a serious caveat and cost, so if you buy one keep it in mind. I will say that the rubber is superbly comfortable, which is very important because this is a large, heavy watch: 44mm by 14mm, 145g. Despite all of that mass, it's super comfortable on my 7.25" wrist and I've worn it to run, cycle, swim and sleep.

Due to the caseback shape, it sits quite low and comfortable on the wrist, and doesn't flop around like some taller watches I've worn. The double AR and domed crystal combine for stupendous visibility at a wide range of angles. You can also see that IWC uses a vertical black flange ringe; functional and invisible. The angled 'ROLEXROLEXROLEX' on current Rolex models for example is one of my pet peeves of flange ring design. Not an issue here on this IWC.