Key Features. Hybrid Active Noise Cancellation & Triple-Mic Noise Reduction during Calls Binaural Low-Latency Bluetooth Transmission 24 Hours of Music Playback (4 hours from single use)IP54 Dust & Water Resistance. Hybrid Active Noise cancellation The W51 come equipped with a new dual-core digital noise reduction chip & more advanced hybrid noise reduction microphones. They are intelligently optimised to detect & reduce every day noises such as from subways & trains. With a noise reduction depth of 35 d B you get an undisturbed listening experience. Triple-Mic Noise Reduction Each earphone comes equipped with triple microphone noise reduction technology & redesigned air ducts to prevent noises of wind. Whether you are in the subway on the bus or riding your bike even a single earphone will capture your voice clearly. Binaural Low-Latency Bluetooth Transmission The W51 adopt the newest Bluetooth low-latency binaural transmission standard to greatly reduce any audio delay. This significantly improves audio-to-video synchronisation making audio lag & signal interference no longer an issue for your music & video experience. New Quality Compensation for Professional Audio Performance OPPO’s first true wireless headphones to be equipped with a system-wide audio quality compensation algorithm to avoid loss of audio quality from noise reduction techniques. The W51 offer quality restoration of the audio for clean uncompromised audio performance. in addition the headphones are equipped with Dual TPU composite graphene diaphragms to provide enhanced audio response & treble performance. IP54 Rated Dust & Water Resistance Structurally designed & certified for IP54 dust & water resistance 6. Whether it is the gym or an outdoor commute listen with peace of mind knowing your headphones are safe..