These high-fired, glazed ceramic lightbulb rings are great for diffusing aroma throughout a room. This diffuser is simple and easy to use, and its compact size makes its ideal for traveling. Just place it on top of a lightbulb, add a few drops of essential oil, and the heat from the lightbulb will diffuse the aroma throughout the room. The ceramic rings are available in a variety of color shades; and also a brass lightbulb ring is available.