Hamilton Buhl HC-HBC nose canceling headphone allows the user to reduce harmful and annoying low frequency sounds in noisy environments. Comfortable for extended use with closed leatherette ear cushion・ which offer added passive noise reduction. The 5 foot braided nylon cord make this unit ideal for use with tablets・ mobile devices and any unit with a 3.5 mm. stereo headphone jack. Runs on one "AAA" battery.Features. Speaker - 40 mm.. Magnet - Neodymium. Sensitivity - 110. Impedance - 32 Ohms. Frequency range - 20-20KHz. Nominal input (Rate power) - 40mW. Maximum input (Power handling capacity) - 100mW. Active cancellation - Up to 20-25dB. Cancellation between 100-500Hz. Cord - 5 ft. braided・ nylon. Plug - 3.5 mm. Stereo. "AAA" Battery Required