the t.bone HD 2000 NC, Noise Canceling Headphones, Circumaural, Active Noise Canceling, Connection via Bluetooth (V 4.1), Up to 6 hours of operation with NC, Up to 10 m range, Impedance 32 ohms, Frequency range 20 - 20,000 Hz, 40 mm Driver, Max. SPL: 97 dB, Includes audio cable with 3.5 mm jack plug and USB charging cable