Superior sound quality and active noise cancellation: the PXC 550-II Wireless delivers Sennheiser legendary sound quality. Active noise cancellation reduces the ambient noise around you and can be adjusted to your preference Exceptional battery performance up to 30 hours: The PXC 550-II Wireless delivers up to 30 hours of battery life. You can travel from London to Hong Kong and back with just one charge One touch access to voice assistant: with the touch of a single button you have access to your AI helper: Siri, Hey Google and Alexa, Frequency range: Speaker: 17 – 23,000 Hz (-10db) Touch pad control: a touch pad on the right ear cup provides volume, play, stop, pause and track skipping control. Touching the ear cup allows you to take an incoming call. Controlling this headset is instinctive and easy Smart pause (activated via the app)/ auto on/off: swivel the ear cups to turn off, sensors detect when you wear the headphone and play/ pause music Alexa built-in devices let you instantly connect to Alexa to play music, control your smart home, get information, news, weather, and more using just your voice.