DuraMOBI Hummingbird Black Technology Bone Conduction Wireless Speaker Portable Small Audio 1. Bone conduction black technology, two-channel, real stereo sound 2. Long battery life, built-in FM, HD calling, HD sound quality 3. Lightweight and small body, easy to carry 4. High sensitivity microphone, diamond knife pattern splitting process 5. The principle of bone conduction, through high-frequency and low-density vibration, the ear bones make a pleasant sound 6. Dual channel, 2 bone conduction transducers 7. Built-in Bluetooth 5.0, FM enhanced IC, TWS wireless stereo 8. Signal to noise ratio: greater than or equal to 70db 9. Shell material: metal 10. Power supply mode: USB charging built-in lithium battery 11. Waterproof grade: IPX 2 12. Audio decoding: support MP3 AC3 AAC WAV and many other 13. Battery capacity: 400mAh 14. Frequency response range: 20Hz-20KHz 15. Interface type: USB 16. Function: music, call 17. Charging time: 1 hour 18. Playing time: 6 hours 19. Standby time: 240 hours 20. Input current: 0.4A 21. Output power: 3W 22. Input voltage: 5V 23. Dimensions: 40 x 25mm 24. Weight: 35g