Tour Travel Size Aromatherapy Diffuser White/Black. Tour is a travel friendly aromatherapy diffuser that fits in your vehicleâ??s cup holder. The ultrasonic technology transforms the interior of your car, or even your kitchen, living room or reading area, into a tranquil space. Its unique design prevents tipping while your vehicle is in motion and the car adapter, included in the box, ensures you can always use it on the go.