Refill your already purchased hanging diffuser or hang a new one! Whenever you run out use the dropper tube or small funnel that comes with your order to refill the bottle, recap, and hang back in your car.
 
This is a set that comes with one vessel of your choice and either a 30ml refill or 15ml refill.
 
*The wooden cap absorbed the fragrance than was previously used so it is advised to order a refill of the same fragrance to get the purest scent.