Felts and Lava Rounds: Choose what color best suits you and your decor or design needs. Stock varies depending on what is  available. Please feel free to request a color and size if you don't see what you are looking for, we will always try and accommodate you if possible,  All necklace and car diffuser's come with one felt or lava insert. If you are wanting  more, for different oils, or just to change it up, additional felts and round inserts are .50 each.