Want to take Essential Oil with you on your drive? These car diffusers clip right onto the vent in your car. The Essential Oil goes directly onto the felt pads, each diffuser purchased comes with 4 different colour felt pads. They are multi-use pads and multiple oils can go onto the front and back of them. These can also be clipped on fans in your home too! It's a great way to take your oils with you on your drive.