Each amber bottle is filled with your choice of 1oz or 16oz of pure fragrance oil. The 1oz bottle comes with a dropper top for easy use, and the 16oz bottle comes with a twist top. These can be used for oil burners, diffusers, and for refilling our car fresheners. Fragrance Oil is measured by weight in ounces. Due to each oil having its own specific density, there will be a variation in volume when comparing each sent.