Lookatool USB Wireless Handsfree Bluetooth Audio Music Receiver Adapter for iPhone 4 5 Mp4 Enable you to enjoy music and voice in the Bluetooth-enabled multimedia or music player wirelessly with a companion Bluetooth Stereo headset. Compact and mini-sized design,easy to take along with. Built in microphone, supports handsfree function. Size: about 6cm x 2cm x 0.8cm. The receiver distance: about 10m (without Block). Supported profiles: A2DP, AVRCP. Bluetooth Specification: V2.1. Instructions for Use: 1. Insert the receiver into the speakers USB interface. 2. Open the Bluetooth enabled mobile phone (or computer), and search the surrounding bluetooth devices to find a device called BT-DONGLE and then its' pairing code is 0000(if asked),after the pairing is successful, the led light will slow down. 3. Then you can select the music via Bluetooth from a cell phone or computer, a great music will play from speaker.