Active Noise Canceling Headest   Headphone with built-in Media Player   Flash Pen         Docking Station   Docking Station Media Player     SD Media Player   3.5"HDD Media Player     2.5"HDD Media Player Specifications: Active Noise Canceling Headset Equal amplitude anti-noise of opposite phase canceling outside noise Hi-Fi Speaker, Low ~ Mid range ambient noise canceling Build in natural sound function Audio: • Driver Unit --- 40mm diameter Neodymium magnet Speaker (32Ω) • Sensitivity --- 110dB • Frequency Response --- 20 ~ 20 KHz Active Noise Reduction (ANC) : • Maximum Active Noise Reduction Level --- more than 17dB in 160~250 Hz • Active Noise Reduction Active Range --- 25Hz~800Hz Features: • Headband --- Adjustable, Foldable (Swivel) • ANC Power ON/OFF • Build in natural sound function