Before you get too excited at the two-birds-one-stone genius of this, know that it’s just a concept or possibly a joke – from all the way back in 2008. In either case, you can’t buy it. At least not yet, so please someone please start a Kickstarter project. Also, one for a soundproof baby helmet.
Update from Nov 2, 2012: Well, someone finally started making these: a website called BetterThanPants is selling them for 40$.