CarAroma Ultrasonic Oil Diffuser This oil diffuser plugs into your car's lighter delivering instant healthful aromatherapy benefits. CarAroma is a sleek plug in diffuser that is wonderful for dispersing your desired essential oil throughout your vehicle! The ultrasonic transducer transforms essential oil into a cool healthful mist. The diffuser can be used as a car freshener, too! Run time full bottle last up to 24 hrs. Modes are 10 sec Interval Off 60 Sec interval