These Aromatherapy Inhalers come in a four piece kit. The inhaler, wick, inhaler plug and the outer protective cover. Simply saturate the wick with the essential oil or oils of your choice, insert the wick into the inhaler and then cap off with the inhaler plug.When sealed closed inside the protective cover the wick and your oils are no longer exposed to the air which will help your oils last much longer. We have had these inhalers last over a month or two and still work great! These work great for respiratory problems and could be used for creating your own Breath easy blends, Calming blends, Energizing / Study blends and more!