OSA High Performance Drainable Louvers are specially designed for superior water protection and meet high free area requirements.With multiple options of blade depths with concealed or exposed mullions this series offers the design professionals with the right selection for the project.These Louvers are recommended for buildings that require adequate ventilation while keeping the elements out.The High Performance series handle higher intake velocities with lower pressure drop across the louver. These models have the added benefits of higher free areas and allowing greater air velocities before entertaining water.