Specification: 1. Driver: 15mm 2. Impedance: 32 OHM 3. Bluetooth version: Bluetooth 5.0 + EDR ( Support for binaural calls) 4. Bluetooth use band: 2.4GHz 5. Power level: CLASS II 6. Output power: 30mW 7. Bluetooth distance: 10 meter barrier 8. Frequency response: 20-20000Hz 9. Operating voltage range: 3.0V-4.2V 10. Mic sensitivity: -42dB 11. With A2DP / AVRCP high quality stereo audio transmission and remote control protocol 12. Powerful noise de-noising circuit (active noise reduction) 13. Talk time is about 2 - 3 hours 14. Music time about 2 - 3 hours 15. Standby time is about 100 hours HOW TO USE: 1> Please check if the headset has entered pairing mode. 2> The name of this earphone would be i7s-tws; 3> Consider it's so small size, you need to adjust the volume on your smart phone, there is only one key button on the earphone, for power on/off/answer or reject phone calls. Note: that there are 3 SKUs, 3 different prices and options! 1. two earphones + charging box, 2. two earphones , 3.single earphone. Reminder: When you open the case, please hold on both short side of the case and gently open it! If you have any problem to pair both earbuds, please contact us first, thank you ! NOTE: When You Charge The Headset Fully, Please Pull Out the Charging Cable Slowly and Softly !!! In Order To Prevent The Lower End of The Headset Off.