This 12-piece set of hanging car air freshener bottles is designed for users who want multiple refillable diffusers for personal use or sharing. The set includes bottles in six colors, with two of each color, and each bottle is empty so you can add perfume, essential oil, or air freshener liquid of your choice. The bottles are made of glass with wooden caps, and the wooden cap is intended to absorb the fragrance and release it slowly. A hanging string is included so the bottle can be suspended from a rearview mirror or other suitable location. The mini size makes the bottles portable and easy to store, and they can also be used in an office, kitchen, bathroom, or cabinet. To use, add fragrance to the bottle, turn it upside down briefly so the perfume soaks into the wooden cap, and hang it in place. Because the bottles are empty, essential oils and perfume are not included. This set is a practical choice for people who like to change fragrances often or who want to prepare several hanging diffusers at once.