While all nebulizer sets will work with all nebulizer compressors (as long as the tubing fits), the same is not true for all neb kits working with all nebulizer masks. This is because masks come in 2 different types: front and bottom loading.
While most nebulizer kits do not come with a mask, it can be an important accessory for added comfort and medication effectiveness. This is especially true for the very young or more mature, as they have a more difficult time properly cupping their lips around the mouthpiece to create the proper seal necessary for a treatment. Masks can also be a way for the patient to relax and breath more deeply without worrying about the mouthpiece.