Sennheiser HD 4.50 BTNC Wireless Bluetooth Headset (506783) is an over-ear wireless headphone designed for everyday use with Active Noise Cancellation (ANC). It features 18 Ohm impedance and a frequency range of 18 Hz to 22 kHz for balanced and detailed sound. Bluetooth connectivity with aptX support ensures high-quality wireless audio. A dual-microphone system provides clear voice calls. It offers up to 19 hours of battery life with BT+ANC and up to 25 hours with Bluetooth only. It also supports wired listening via a 3.5 mm jack.