ANKER SoundCore Liberty 4 Pro Bluetooth Wireless Earphones 1. Bluetooth version: 5.3 2. Transmission distance: about 10-20m 3. Use time: about 30-40h (support super fast charging) 4. Interface: Type-C 5. Packing list: headphones x 1, charging cable x 1, ear caps x 6 pairs 6. Charging compartment size: about 6.46 x 6.17 x 2.96cm 7. Weight: single earphone about 5.5g Features: 1. 6 sound sensors to cover multi-band noise, 1 barometric pressure sensor to adapt to the air pressure environment of high altitude flight, providing stable noise reduction effect 2. Adjustable ambient transparency mode or noise reduction mode through APP or Touch Bar 3. ACAA 4.0 coaxial dual-unit acoustic architecture, equipped with digital crossover technology, high, medium and low frequency smooth articulation, the whole link to perceive the real good sound 4. Bluetooth transmission technology, can transmit 3 times (or more) than the AAC or SBC encoding data volume, bring high-resolution music enjoyment 5. Fixed sound field or head tracking mode can be selected, the sound changes with your movement, bringing a more realistic sense of immersion 6. 6Mic + AI call noise reduction system, intelligent recognition and separation of human voice and environmental noise, clear voice calls anytime, anywhere 7. APP open intelligent dialog mode, the headset can detect the human voice dialog, no need to take off the headset, you can also easily talk to each other 8. Bluetooth 5.3 connects two devices at the same time, switching freely without disconnecting 9. Finding anti-lost, with the help of APP to let the device beep to determine the location of the headset or charging bay 10. Ergonomic streamline design, solid fit to the ear, highly flexible silicone ear caps, automatic adjustment of the shape, 30-degree inclined into the ear design, natural fit to the ear canal 11. 6 pairs of silicone ear caps, fit various ear shapes, more comfortable and stable to wear 12. Sliding lid charging cas