Everything that hangs from a rear view mirror smells like a chemistry set. This does not, because you decide what goes in it.

A small vented clip with reusable felt pads. Add a few drops of any Dolphin Clinic oil to a pad, close the catch and clip it to a car vent. Change the pad when you want a different scent.

Dolphin Clinic's own suggestions are worth borrowing: lemongrass if the dog travels with you, peppermint for long drives, Stress Less or Sheer Bliss for the commute home.

Comes with spare pads and a carry bag.

No aerosol, no plastic tree, and no synthetic fragrance unless you put one in yourself.