The portable Orb™ Diffuser is specially designed to be spill-proof, making it ideal for the office, the car or at home, and provides intermittent (blue LED light) or continuous (green LED light) diffusion for up to 4.5 hours. Peppermint is a great oil to diffuse for those long car rides.  En-r-gee and Purification essential oil blends are also favorites for the car!