Sony MDR-NC5

Reduces Noise by 70% (10dB) when noise canceling circuit is switched on
Ideal For Travel -- lets you hear music against a quieter background on planes, trains, busses and cars; quiets noisy air conditioners
Ideal For Outdoor Use when gardening or on a noisy street
Noise Canceling Circuit actually senses outside noise with built-in microphones and sends an equal-but-opposite canceling signal to the headphones; cancels noise from 40Hz to 1,500Hz, more than 10dB noise cancelation at 300Hz where the human ear is super-sensitive
Noise Canceling On/Off Switch with red Power LED to indicate when Noise Canceling is operating; when Noise Canceling is off, headphones continue to function for music listening
Open-Air Headphone Design for lightweight comfort, hour after hour
30mm Diameter Driver delivers deep bass down to 30 Hz; provides outstanding dynamic range
Neodymium Magnet for maximum energy in minimum size; ounce for ounce, Neodymium is far more powerful than conventional Samarium Cobalt, Ferrite or Aluminum magnets; helps produce ample sound output 100 dB sensitivity (NC on)
Folding Headband and pivoting earpads make for easy storage in a backpack, briefcase or puse
Supplied Carrying Pouch for easy portability
Supplied Airline Plug Adapter for compatible in-flight entertainment systems
Extended Battery Life approximately 46 hours with a single AAA battery
Type: Open-Air, Dynamic (with Noise Cancellation)
Driver Unit: 30mm
Magnet: Neodymium
Headband: Folding Type
Power Source: 1 AAA Battery
Battery Life: Approximately 46 hours (alkaline)
Power Switch: Manual
Noise Reduction: More than 10dB at 300 Hz
Impedance: NC Power On: 17 ohms
NC Power Off: 35 ohms
Sensitivity: NC Power On: 100 dB/mW
NC Power Off: 98 dB/mW
Noise Cancellation Frequency Range: 40 - 1,500 Hz
Frequency Response: 30 - 15,000 Hz
Cord and Plug: 4.9 ft. (1.5m) cord with Gold-plated stereo mini-plug