The active holder charges your Galaxy S7 when it is in the holder. You can choose to connect the cig-plug to the car's 12 Volt socket, or to remove the cig-plug adapter and connect the USB cable to the car's (or stereo's) USB connector.
The holder is attached onto a tilt swivel and can be adjusted in order to avoid light reflection. 12 Volt. Attach the holder onto a ProClip Mounting Platform in your car.