I am a road trip junkie. Saje essential oils and blends work wonders for fatigue, mood and staying calm. I assumed that with the addition of heat from plugging the unit in, this vehicle scenter would have the ability to have lasting power. NOT TRUE! Numerous times I tried saturating the pad, replenishing daily, using blends or using single oils but nothing worked. The scent lost its strength within a couple hours. I gave up on this method of scenting my car and am stuck with the unit and a multitude of these useless scent pads because I stocked up on them so that I would never be without. Maybe natural doesn't work in the car and I'll have to go back to one of the artificial chemical brands for the car.