The Scent Bottles Montessori material develops the sense of smell by matching different scents. The set consists of twelve hollow wooden cylinders, each with a removable perforated top and a coloured cap (six red and six green), as well as two wooden trays with six insets each to hold the bottles. The perforated caps fit loosely, and so can be easily removed for filling or emptying the bottles. Dry materials, such as whole spices or dried flowers work well, however as the interiors of the bottles are unfinished wood, we do not recommend filling them with liquids as the wood could absorb them and be permanently tainted with that particular scent. Instead, insert a cotton ball, cotton pad or a small piece of sponge and then add a few drops of the liquid in a concentrated form, such as essential oils.