Sony MDR-NC6 Noise Canceling Headphones (Discontinued by Manufacturer) Reduces exterior noise by more than 70 percent (10 dB at 300 Hz) so you can hear music against a quieter background Active noise reduction from 40 to 1,500 Hz using 1 AAA battery (not included); extended battery life approximately 30 hours Compact size and folding design allows easy storage in a backpack, briefcase, or purse Noise-canceling on/off switch; headphones work with or without power Includes soft carrying case and airplane adapter plug