The Amrita Ball is plugged into an electrical outlet. After placing 10 drops (maximum) of an essential oil or blend on the felt pad, insert the pad into the ball. After five minutes, your essential oil will diffuse up to three hours in an area up to 500 square feet. An inexpensive, convenient way to diffuse essential oils; excellent when traveling. Includes 10 reusable felt pads. Replacement pads are available.