I got these clip on air fresheners for two reasons: #1.) I like bees #2.) I like being able to pick my own scent of air freshener. I have a couple of essential oils and can tell you this - make sure you get a quality oil. There are so many nice scents - floral, earthy, or fruity - you pick. If you're not sure, some popular scents like rose, lavender, pine, lemongrass, etc are all good choices. Once you have an oil, use a dropper and apply a few drops of oil to the little felt-like pads, insert them into the back of the clip, and affix to vent. Because my vents are horizontal, my bee is horizontal, but I don't mind. I just hope the little oil pad doesn't fall out as the insert opening is now on the side. Seems like the clip should rotate (but doesn't) as that would solve that. That aside, these clips are unique, look really pretty, and are scent-customizable. I'm pleased with them and if you have a favorite scent, you'll like using these too.