22 unique pre-installed sounds include 10 digital fan sounds, 10 white, pink and Brown noise variations, and 2 varieties of ocean sounds to make sure you’re getting the right sound to get you to sleep Disrupts environmental noises to ensure you fall asleep in a soothing environment Safe, powered by AC or USB Volume control lets you adjust the volume to your ideal level of relaxation Optional timer means you can set the LectroFan Evi to turn itself off once you’ve drifted into a deep sleep 3.5mm connector for headphones or portable speaker offers the flexibility of hearing the sounds the way you want