Bluetooth version: CDN 5.0 Voice: Support Support protocol: A2DP1.3/HFP1.6/HSP1.2/AVRCP1.6/D11.3 Battery capacity: left and right earphones: 45 mAh, charging box: 400 mAh Charging power supply: AC input 110-240V; DC output 5V Transfer power: Class2 Wireless Frequency: 2.402-2.480GHz Call duration: about 3-5 hours Music Play: about 3-5 hours Charging time: 1.5 hours Denoising: Intelligent denoising technology of DSP Operation Range: 15 m Effective Distance Charging Interface: Micro-USB