The Shelly the Turtle exclusive ultrasonic diffuser is easy and fun for kids to operate and has a host of features, including: Diffusion, light, and sound combinations to set the stage for playing or winding down Up to 5–6 hours of continual diffusion or 10 hours of intermittent diffusion Touch-sensitive flippers and 10 different lighting options to fit any mood A built-in speaker with five white-noise variations to drown out outside noises and support sound sleep through the night