Car Diffusers With Essential oils. Glass 8 ml bottles are made by blending a diffuser oil + essential oils and can be hung from your rearview mirror or in a small space in your home. The diffuser bottle is shipped with a plastic plug under the wooden lid. Remove the plastic stopper and replace the wood lid, then gently tip the bottle to allow a little bit of the fragrance oil to soak into the wood lid. Then just turn the bottle upright and hang! Available with the following scents: lavender lemon tranquility patchouli prairie flowers grapefruit lavender patchouli peppermint eucalyptus