The present invention generally relates to an air freshener mounted on a bottle, an aerosol container (2), or the like, diffusing fragrance or essential oil therein, comprising； a cap (1) consisting fragrance, essential oil, aromatic compounds, additives, polymer, copolymer, monomer, resin, PVC, wax, or paraffin, or a combination thereof. Alternatively, said cap (1) is disposed an outer shell (11) and an inner shell (13) therebetween.
