Respiratory protection is a device or garment designed to protect the respiratory system from harmful particles, gases, vapors, or other hazards. There are several types of respiratory protection devices, designed differently depending on the type of hazard and the work environment. A commonly used respiratory protection device is the respirator, which uses either particulate filters or gas filters to filter hazardous substances from the air before they are inhaled. These masks can come in a variety of styles, from simple disposable masks to reusable masks with replaceable filters.