Greenheck High Performance Axials, Model RA, are direct driven axials designed for inline air ventilation in commercial, institutional or industrial buildings. The casing design and construction are well suited to indoor or outdoor applications and can be easily installed in ducted or nonducted systems. The RA is designed to significantly reduce operating costs and is the most efficient inline fan manufactured by Greenheck! Additionally, the RA blade design offers inherently lower sound levels than typical axial fans.