The unit seems fair priced at around US$170 but the cartridges are around $50?! Does anyone have pics of the cartridge and how it works? Do you keep the unit in the growroom (closet) or outside the growroom?The clean, fresh fragrance is based on a blend of eucalyptus and pine oils, creating an effective, natural odor neutralizer. The powerful ingredients make it ideal for treating areas with severe malodor problems.