The Fidelity FEP-NCTB Noise Cancelling Headhones with Titanium Drivers from Aiptek passively block background noise naturally. The active noise cancelling circuit inside the control box is designed for filtering ambient noise out, and works best at mid/low frequencies. This in-ear noise cancelling headphone includes two microphones mounted on the earpieces to monitor the ambient noise signal. This circuit attenuates ambient noise by 12db. Their in-the-ear design provides a great personal music listening environment. Soft silicon sleeves fit securely and comfortably in the ear canal. The user can choose to switch the noise cancelling feature on or off. Other features include independent volume control, dynamic bass and treble response, and a blue led power indicator. Product specs are 10mm titanium speaker drivers, 104 db/+/_ 3db sensitivity, 3.5mm audio plug, and 20Hz to 20kHz frequency response. This product is powered by one AAA battery.