The Pebble Fan Diffuser is waterless and lightweight so, it won't slow you down when you are on the go. Charge up the lithium battery to enjoy 8 hours of continuous diffusing. The Pebble has 20 DB quiet operation. All you notice is your favorite scent. Each Pebble comes with four paper pads. Use a new paper pad when it stops absorbing fresh oil or when changing scents. Paper Pads Refills sold separately. To use, add 5-10 drops of essential oil to the paper pad. Close the cover and turn on the diffuser.