NOSK (personal air filtration system) block hazardous substances, such as airborne dust, allergens, hay fever and air pollution. NOSK is developed and designed by top ear, nose, and throat specialists to provide natural aid to allergy and asthma sufferers. Proven to reduce the inhalation of pollutants and allergens, NOSK provides natural relief for asthma and allergy sufferers by improving the quality of air that they breathe.