Califone NC500TFC Active Noise Cancelling Headphones; Frequency Response 20Hz &ndash; 20kHz; Input Impedance 80 ohms with noise-canceling off, 20 ohms with noise-canceling on; Sensitivity Input 1kHz @ 1mW: 105 dB with noise-canceling off, 114 dB with noise-canceling on; Total Noise Reduction around 23 dB; Output Power 30mW; Replaceable Leatherette Earpads; Uses included 2 AAA Alkaline batteries; Battery Lifetime approx 35 hours depending on usage Califone NC500TFC Active Noise Cancelling Headphones; Frequency Response 20Hz  20kHz; Input Impedance 80 ohms with noise-canceling off, 20 ohms with noise-canceling on Sensitivity Input 1kHz @ 1mW: 105 dB with noise-canceling off, 114 dB with noise-canceling on; Total Noise Reduction around 23 dB; Output Power 30mW Replaceable Leatherette Earpads; Uses included 2 AAA Alkaline batteries; Battery Lifetime approx 35 hours depending on usage 5 feet Replaceable Straight Cord with in-line volume control & included 3.5mm plugs; Adapter 3.5mm to 1/4" audio adapter included; Hard storage case with internal storage pouch; Headphone, case & accessories weight 17 ounces; Shipping Weight 2 pounds