Infant 50-Pack, Professional Series The lung bags in this 50 pack are sized specifically to fit the PRESTAN Professional Series of Infant CPR manikins. Insertion of the one-piece lung bag design is a breeze! Fold it up, slide it in and you are ready for training. No tools necessary! The instructions for use refer to this product as a "face-shield/lung-bag," because the exposed part of the product covers the face of the manikin, keeping it free of germs. If the manikin is not shared by students, then no additional face shield is necessary. The addition of a filtered face shield to protect students from cross-contamination is necessary if the manikins are shared by students. Filtered face shields are sold separately.