Nebulizer breathing treatments are used for patients who need medication specially applied deep into the airways and lungs. Nebulizer devices transform liquid medication into droplets and administer doses to patients in a mist. The mist is pushed through a tube with compressed air, in the most commonly used models. Dosages are inhaled directly through the nose or mouth, either through a mouthpiece or a mask. Nebulizer breathing treatments are most often employed for cases of asthma, chronic obstructive pulmonary disease (COPD) and chronic bronchitis. Weakened lungs may make it difficult to inhale deeply, quickly or fully, as some regular inhaler medications require. Doctors prescribe nebulizers for patients who cannot use handheld inhalers effectively. Elderly patients are most likely to receive nebulizer asthma treatments for respiratory system medications such as Albuterol and Ipratropium. While technology in nebulizers is evolving, compressed-air or "jet" nebulizers are still the most widely used. These consist of an air compressor, nebulizer kit (where the medicine goes in) and tubing/mouthpiece (where the nebulized medicine comes out). Doctors will prescribe nebulizers with face masks for immobilized older patients. Nebulizer breathing treatments usually last from 5 to 30 minutes.