Edifier X3 Air Wireless Stereo Bluetooth Earphone 1. Bluetooth version: Bluetooth V5.3 2. Bluetooth protocol: A2DP, AVRCP, HSP 3. Effective distance: about 10m 4. Power supply: lithium battery included 5. Usage time: about 6.5h (headset) + 19.5h (charging case) 6. Input: 5V-200mA(headphone) 5V-1A(charging case) 7. Frequency range: 20Hz-20KHz 8. Sensitivity (SPL): about 94dB 9. Packing list: charging case x 1, headphones x 2, earbuds x 4, charging cable x 1 Features: 1. Lightweight and compact, comfortable to the ear 2. Master-slave switching, seamless connection 3. 0.06s low latency rate, audio and video synchronization 4. Bluetooth 5.3 chip, fast connection, stable signal 5. IP55 level dustproof and waterproof, easy to cope with sweaty sportsrainy day traveling 6. AI call noise reduction technology, accurately recognizes and separates environmental noise and human voice, removes noise interference, clear and stable calls 7. Balanced tri-frequency, rich in detail, beautiful vocals, layered, natural and real 8. Connect with Edifier Connect APP, support rich customization settings