1.Stable Connection: Bluetooth protocol and FM transmission stream music straight from your phone to your cars stereo system.2.Rapid Charging: Dual USB power outputs (5V 2.4A ) charge two devices simultaneously.3.Hands-Free Calling: Answer, Hang-up, or reject a call with the built-in microphone system.4. Universal Compatibility: Works with any smartphones or other devices with Bluetooth and it even can play music from USB Flash Drive. 5.Contact type springNo matter the size of the cigarette lighter, there will be a good contact surfaceInternational environmentally friendly high-flow PC material, black translucent effect, when the display is off, you can't see anything inside the machine, high-end atmosphere