Delta's AROMATHERAPY Writing Instrument Collection is unprecedented. These pens feature a special vase INSIDE the specially designed clip. Simply unscrew a sphere at the top of the clip. It is the handle of a special wooden oil-wand which is immersed in essential oil for approximately 20 minutes. Once the wand is saturated, the beneficial aroma will last about 2 weeks. Delta includes a specially formulated, 10ml vial of essential oil with every pen in the collection. Each different scent was developed for its ability to offer a sense of well being upon application to the skin!!!. Each collection matches each individual scent.