Pick your favorite oil and use with the disk. This is a do-it-yourself car refresher.  You will receive a plain wood disk with a  .6 ounce oil that you can use to replenish over and over! The fragrance oil can also be used in water diffusers and warmers. 
 
Instructions: Apply one dropper of oil to the front. Let it dry about 8-12 hours... then repeat on the other side. I usually do it about 3-4 times on the back before hanging in the car. Make sure the oil dries into the wood each time before reapplying.