Venturi air horns 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 a 3" intake and a light weight of only 10 lbs. Manufacturers include Texas Pneumatic, Allegro and other trusted brands.