Transform your home or car audio system to Bluetooth wireless, the worlds tiniest music receiver, and stream crisp, high- quality music from your smartphone or tablet. Hands-free calling with the built-in microphone makes catching up with friends a breeze. Built-in Mic Battery-Free Latest Bluetooth 5.0Function: music play and hands-free call Connect 2 Devices at One Time Bluetooth Version: 5.0 Connect the USB and AUX together when use With MIC Bluetooth Protocol: A2DP/HFP Support SBC/AAC Frequency range:2.402GHz-2.480GHz *Frequency Response: 20Hz-20kHz Output Power: 33mW, RL=16Ω SNR(Signal to Noise Ratio):>90dB Sensitivity: -42?3dB Transmission distance: up to 10m THD+N ( total harmonic distortion ):<0.05% Bluetooth Delay: <200mS USB interface working current:130mA/5V Indicator Lights:LED Red and Blue