At DSA ’12 Walther was exhibiting their Walther PPQ NAVY 9mm pistol.
The NAVY version is designed for use in situations where the pistol may become immersed and/or fired in water. A hole and guides in the striker channel, allowing water to be drained or pushed out, along with a stronger striker spring allow it to be used when completely flooded.
In Germany the NAVY Tactical version (threaded barrel) can be bought with a matching suppressor. Those lucky Germans!
[ Many thanks to Lionel for emailing us the first two photos and information. ]