Bluedio TWS T-elf Bluetooth Version 5.0 In-Ear Bluetooth Headset with Headphone Charging Cabin(Red)

1. Bluetooth version: 5.0 2. Transmission distance: 10 meters 3. Battery type: built-in lithium polymer rechargeable battery 4. Function: Voice over IP: Support 5. Music playback: support for devices with Bluetooth 6. One for two functions: support 7. Voice prompts: Four language tips 8. Caller ID: Not supported 9. Standby theoretical time: up to 249 hours 10. Call theory time: up to 12 hours