The Terra Smart Tower Diffuser can scent spaces as large as 2,000 square feet, making it ideal for expansive and open floor plans. Furthermore, its 500mL fragrance capacity means your fragrance can last a very long time between refills. Simply plug in the Terra Diffuser, install your favorite fragrance oil, and customize your scent schedule with the intuitive "Aroma-Link" app. The Terra Diffuser comes with an empty oil bottle and power supply. It's easy to maintain. Just run our Diffuser Cleaner (or equivalent) every 3 months in a well ventilated space (or when you change oil). This simple maintenance will keep you enjoying amazing fragrance for a long time from your Terra Diffuser.