AirLife Empty Nebulizer helps you take your medicine that requires inhalation when an inhaler will not do. This allows the medicine, such as steroids, to get directly into the respiratory system that they are aiming to treat for quicker treatment. This quicker treatment can be a critical component in saving lives. Also, this empty nebulizer can adjust the Fi - O2 settings between 35% and 100% in the 350 mL version and 28% to 98% in the 500 mL option. Fi - O2 stands for fraction of inspired oxygen. This fraction or percentage indicates the amount of oxygen that is present in gas-exchange, or how much oxygen is being delivered to the bloodstream from the lungs. - Features:Adjustable Fi - O2 to Meet Individual Needs - Delivers Medication Directly to Respiratory System - Can Work When Inhalers Fail