FM transmitters allow you to play music or other audio from your phone with your car speakers by using a FM station. The station must be one that is not used in your area to avoid a static connection.
AUKEY AiPower enabled USB ports provide the safest maximum charging speed for all your different devices for a healthier battery function. The green color identifies the AiPower ports on your AUKEY products.
Yes, they can stay plugged in when not in use. However even if the car is not running, the charger will continue to use a small amount of battery power, even if there is no device plugged in. This could affect the battery of your car if it is not driven for long periods of time.