Air Systems International Auto-Air Series Breather Boxes are used to ensure the safety of personnel working in areas with potential air contaminants, specifically carbon monoxide (CO). They continuously monitore CO levels and provide real-time alerts to protect workers from exposure to toxic gases. They find application in confined spaces like tanks, manholes and tunnels, where proper ventilation and air quality are paramount. These breather boxes provide Grade-D filtration, delivering breathable air for designated workers. They have a filter change indicator on all filtration stages to indicate the replacement of a contaminated filter.