Attaching it to a car vent diffuser, simply clip onto your car vent and add a few drops of your essential oil(s) to the wool pad included. Enjoy!! Repeat as necessary. Includes 3 wool pads in random colors. Directions: -add drops of essential oil(s) on to the included pad -Insert wool pad into the back opening of clip -Clip onto air vent (clip slides out so can be attached vertically or horizontally) -Repeat as required -Wool pads can be washed as needed. Each car vent diffuser will come nicely packaged with above instructions.