The Ventex 2420/2425 louver incorporates a specially engineered stormproof blade design that maximizes the free area of the louver. The design increases the free area of the four inch louver by nearly 30% over traditional construction. The 2420/2425 is the most versatile louver Ventex offers and is available in a large variety of custom geometric shapes. With its extensive list of options and accessories it can be customized to fit almost any application. Model 2420/2425 is AMCA certified for both water penetration and air performance.