Ultra-Durable Construction: Crafted from premium heavy-duty galvanized steel panels, this shutter exhaust louver vent delivers exceptional corrosion resistance and weatherproof performance, ensuring reliable operation even in harsh environmental conditions. Product Dimensions: The external dimensions of this 30-inch automatic gravity shutter measure inches 33 inches(L) × 33 inches (W) × 3.1 inches (D). Efficient Automatic Gravity Operation: This louver vent can automatically open and close with the airflow to meet different ventilation needs. Its self-sustaining gravity system ensures 24/7 freshness while keeping out dust, pests and storms. Versatile Applications: This shutter exhaust louver vent is engineered for use in residential attics, warehouses, workshops, industrial facilities, basements, barns, and greenhouses. Pay Attention: This automatic gravity shutter is sold separately, and the exhaust fan blades and motor are not included in the package. Made of high-grade galvanized sheet, this high-quality shutter louver vent is easy to install and maintain, durable and corrosion-resistant.