The 2013 beta version, Glass Explorer, distributed (for $1500 each) to 8,000 lucky app developers and consumers who submitted a winning 50-word response to the hashtag #ifihadglass, focuses on functionality. Commands are issued via either a microphone or touchpad, both of which reside on one arm of the glasses frame. Headphones are unnecessary due to bone-induction technology, which transmits sound via skull vibrations.