Doosl Universal Wireless FM Transmitter Audio Adapter Car Kit Doosl® FM Transmitter  Features:  Listen to your favorite music on your car stereo  Easy-to-read digital display  Convenient to control  The last FM frequency memory function  Built-in soft light, will not cause distraction in car  Hand free calling for safe driving  300mAh rechargeable battery, up to 10 hours playback   Specifications:  Effective Range: approx. 15ft  Frequency Range: 88.1-107.9MHz  Power Supply: inner 300mAh Li-Battery charging via Micro USB cable  Operation Time: up to 10 hours (built-in battery) music playback  Charging Input：DC 5V  Dimensions: 62*25*14 mm   Package includes:  1 x Doosl® FM Transmitter  1 x User Manual  1 x 18 months Warrenty Card   FAQ:  1 How do I run the Doosl® FM Transmitter?  Simply operate the FM transmitter by following three steps:  1. Turn on your car stereo and select a blank and clear frequency which is without any interference from 88.1-107.9MHz.  2. Connect the Doosl® FM Transmitter with your device via 3.5mm audio jack, and adjust to the same frequency as the car FM radio.  3. Now enjoy your favorite music!