A pair of AAA batteries goes inside the left Dr Dre Beats earcup, and the right side offers two controls. There's a master On/Off switch with a red indicator light Beats by dre Butterfly, and pressing the large "b" emblem mutes both the music and the noise cancellation, should you want to discuss tyfitsb20110720 your drink cart options with the flight attendant without removing the headphones. They fold Dr Dre Headphones and unfold with a pair of locking hinges, but we must take care not to overextend the rigid plastic headband when putting them on or taking them off, lest calamity occur. The Beats By Dre Headphones must be powered on--which again automatically engages the noise cancellation--in order to deliver the music.