These Venturi air horns are excellent for ventilating confined spaces. They work by creating large volumes of air suction to extract potentially harmful gases and fumes from the air, then discharging them out of the sizeable cone-like opening to disperse the air effectively. This makes them extremely useful in confined space ventilation. These air horns are powered by compressed air and feature a maximum PSI of 40 to 100 PSI. Additional specifications include an 10" intake and a weight of 43 lbs. Manufacturers include Texas Pneumatic, Allegro and other trusted brands.