Smof Bluetooth 4.1 Receiver A2DP Multipoint Connection Wireless Audio Adapter/Bluetooth Hands-Free Car Kit with Built-in Mic&3.5mm Aux Port for Home Stereo Sound System Hands-free Calling:Built-in microphone,you can receive /answer your calls with your hands free when your are driving;Bluetooth 4.1 combining A2DP comes with stable connectivity and remarkable signal stability Two-Link: Can connect two Bluetooth devices at the same time.Bluetooth range reaches up to 30 feet in open space without obstacles;Freely enjoy music or answer phone calls Built-in battery provides up to 8 hours' play and talk time,only takes 1.5 hours to fully charge it.Smooth call conversation and non-stop and clear music streaming creates enjoyable listening experience Wide Compatibility: Compatible with most Bluetooth enabled devices like smartphone, MP3, tablet, and A/V receivers using RCA or 3.5 mm jacks.etc, ideal for home or vehicle audio systems Small,simple and portable;Support A2DP/CLASS 2/AVRCP;SBC, MP3.Some cars may have humming noise when used with it,you will enjoy clean music if work with a ground loop isolator