With the Venta Fragrance Composition classic you get three different bottles of fragrance oil of 50 milliliters. The package contains both a winter, a citrus and a relaxation bottle, so you can adjust the fragrance to your own needs. The oil is suitable for all humidifiers. If a humidifier does not have a fragrance compartment, then you simply put drops of fragrance oil in the water. You only need a few drops for a delicious fragrance.