We've seen plenty of headsets with built-in volume controls, which do sometimes come in handy when you've got your audio player in a pocket or bag and need to quickly turn the sound down and actually listen to another person. But only in Japan would the volume button be tagged as a "Manner" function. As far as we can tell, the Manner control on Pioneer's SE-E55 headset instantly lowers the volume so that you can interact with those around you in a polite manner. Nice. A little too nice for us, of course, but not, apparently, for our friends in Japan.