The Sennheiser Momentum 4 Bluetooth Over-Ear Headphones are audiophile-inspired with a 1.65" (42mm) transducer system that delivers brilliant dynamics, clarity and musicality. Adaptive Noise Cancellation automatically adapts to ambient noise. It features outstanding battery life with up to 60-hours of play back time with fast charging Bluetooth 5.2 compatibility. The Digital Beamforming Microphone system employs 2 mics on each ear cup: simply touch interface on the right ear cup for music, ANC, calls and voice assistant to ensure effortless ease-of-use.