The Shell Ultrasonic Aroma Diffuser fills your home with the scents you love. The Shell Diffuser runs up to 4-hour continuously or up to 8-hour intermittently. Customize your relaxation with the 60, 90, 120-minute timer and 7 LED lights. The 7 LED lights can rotate or be fixed to one color. To use, add water and the essential oil of your choice, turn it on, and let the cool mist relax and restore you.