FineSource Mini Bluetooth 4.1 Receiver A2DP Wireless Adapter for Home Audio Music Streaming Sound System & Bluetooth Car Kits with 3.5 mm Stereo Output for Smartphones & Tablets Music or call switching, free and relaxed. Super clear and flow conversation effect. Simple and Easy Wireless Set-Up, Automatically connect, if you need the cell phone connect the receiver automatically, just turn on the Bluetooth of the cell phone first, and then turn on the Bluetooth receiver Simple operation, normal speaker become hands-free Bluetooth speaker magically, portable for vehicle mounted systems. Two-link: can connect two Bluetooth devices at the same time. Over length receiving distance, can reach up to 30 feet in open space without cables. Extra-long built-in battery provides up to 10 hours playing time and only need 1.5 hours to charge it fully. NOTE: This is a receiver not a transmitter.