This is a non-rebreather mask available in a size for an adult. When used with the attached reservoir bag, this product lets you administer high concentrations of oxygen. Non-rebreather masks also prevent the breathing of outside air, that is, air that’s not coming from the included reservoir bag. This then gives you more concentrated oxygen to help make breathing easier. This mask also has a low resistance check valve that prevents the rebreathing of exhaled gases. The mask itself is made of odorless vinyl, and includes 7′ of tubing and an adjustable nose clip.