Sony MDR-NC11 Fontopia Noise Canceling Headphones with In-line Volume Control Reduces exterior noise by more than 70 percent (10 dB) so you can hear music against a quieter background Tiny size allows easy storage in a backpack, briefcase, or purse Extended battery life approximately 60 hours with a single AAA alkaline battery Noise-canceling on/off switch; headphones work with or without power Includes soft carrying case and airplane adapter plug