Black Walnut Wood Essential Oil Diffuser For Your Car. (Dark color only.) Simply insert the magnetic clip in your car's air vent, add your favorite essential oil to the center of your wood flower, rotate the flower around for maximum absorption, and attach it to your clip. When the scent fades, add more oil. Avoid harsh chemicals. Avoid unattractive air fresheners. Avoid more trash in the landfill. Magnetic clip is included. Avoid water on your diffuser, as this may damage the wood. ***THESE ARE SELLING LIKE HOT CAKES IN OUR LOCAL BOUTIQUES.***