Automatic opening/closing louvers on exhaust side (closes naturally when fan stops, dust and rain resistant), safety screen on intake side; high airflow, low-noise, low energy consumption, long service life. Industrial workshops with high temperature, stuffiness, odor, smoke, or dust;comprehensive or localized ventilation and cooling for agricultural greenhouses, livestock farms, warehousing, and commercial premises.Housing: high-strength galvanized steel or corrosion-resistant FRP; blades: stamped aluminum alloy or nylon-reinforced iron.