Positive pressure ventilators, designed for the removal of airborne dust contamination, fumes, high ambient temperatures and other environmentally sensitive materials processed on construction and industrial job sites. High static capacity, five blade MultiWing, axial- type propeller. Equipped with reinforced composite annular ringed, propeller enclosure of all steel construction, powder coated for resistance to corrosion and internal damage. Rubber anti-vibration mounting with 2.80/2.50-4 pneumatic tires rated for non-highway use. Over center, friction type parking brake system, designed to be deployed as necessary to prevent machine movement on the job site.