<b>Technical specifications</b> <br>Brand Name: Bluedio<br> Model Number: T-Elf 2<br> Bluetooth version: 5.0<br> Frequency range: 2.4 GHz-2.48 GHz<br> Support protocols: A2DP, AVRCP, HSP, HFP<br> Frequency response range: 20Hz-20KHz<br> Standby time: about 1000 Hours<br> Music/Call Time: About 5-6 Hours<br> Charging time: About 1 hour for earphone and 2 hours for charging case<br> Input voltage/current: 5V/>100mA<br> Output power: 7mW + 7mW<br> Line Length: None<br> With Microphone: Yes<br> Resistance: 32Ω<br> Function: For Mobile Phone,HiFi Headphone,For iPod,Sport<br> Support Apt-x: No<br> Style: In-Ear<br> Communication: Wireless<br> Active Noise-Cancellation: No<br> Is wireless: Yes<br> Vocalism Principle: Dynamic