The amazing thing with this scent diffuser is that it only requires 2-3 drops of essential oils every time you wear it for all-day aroma therapy. It doesn't use water, it doesn't need electric power; The density of the felt pad has been especially designed for an ideal diffusion. OR... you can even skip the essential oils and just change out the pad color to match whatever you are wearing that day. Taking this a step further you can even make your own background color pads with felt or leather to create different color effects.