These car fresheners are made with essential oils & reed diffuser 
They come in these attractive diamond shape bottles
 
All you do is Unscrew the bamboo top ,remove the plastic cork replace the bamboo top on the bottle hold upside down for less than 10 seconds and the top will start to turn a little dark and that tells you that the bamboo cap is charged and ready to be used. They last approximately two months. You can put them in the car, just hang them from your rearview mirror, or buy them for your closets , hang from Lamps etc.