Dland Car Kit MP3 Player Wireless FM Transmitter Modulator with USB/SD/Card Reader MMC Slot and Remote Control Functions (BT310) 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. Music or call switching, with pure and clear sounds. Simple operation, normal speaker become hands-free Bluetooth speaker magically, portable for vehicle mounted systems. Extra-long built-in battery provides up to 8 hours playing time and only need 1.5 hours to charge it fully. Two-links: with the functions that can connect two Bluetooth devices at the same time. Over length receiving distance, can reach up to 30 feet in open space without cables.