Inflatable fenders?! Yeah, turns out to be Topeak's AirFenders.
These fenders stow neatly in hydration pack or wedge bag until needed. Then a few pump strokes is all it takes to inflate the fender protecting you from mud and road spray. Once skies clear, the AirFender™ Front and Rear deflate, roll up and clip compactly for easy storage. Multiple pivots on the Rear are easily adjustable allowing for optimum tire clearance on virtually any bike. Handy quick release makes installation and removal a snap..
Interesting concept as it addresses lightness and compact-ability, though I personally wouldn't bother with these on a commuter/everyday bike. Perhaps practical on a road bike since it snaps on/off?!