Key Features. Binaural Low-Latency Bluetooth Transmission Dual-Microphone Noise Cancellation for Call Wearing Detection Automatic Play and; Pause 3.5 Hours Playback Time Up to 15 Hours with the Case IP54 dust & water resistant. Fast Stable & Smooth Connection Instead of having a primary & secondary headphone audio can be transmitted to both ears at the same time which ensures a fast & smooth transmission. Meanwhile system wide optimisations designed to eliminate delay lag incompatibility & other disturbances help to maintain your signal quality for & undisrupted listening experience Dual-Microphone Noise Cancellation during Calls Noisy surroundings cannot compete with your voice during calls thanks to dual-microphone beamforming an environmental noise cancellation algorithm & an anti-wind noise chamber Wear Detection Automatic Play and; Pause Infrared optical sensors detect whether you're wearing the headphones or not & therefor will pause or play your audio in response so you don't need to take out your phone each time. Carefree Listening The W31 headphones are designed to resist water & dust at an IP54 rating. Whether you're staying in or working out you will have confidence that your earphones are protected Enjoy Your Personal Soundtrack All Day Enjoy up to 3.5 hours of continuous music before re-docking the charging case holds up to 15 hours-worth of enjoyable music playback..