The Helios HDH 250 is a robust horizontal roof ventilation cowl engineered to cover rooftop convection vents and supply air outlets. It shares the same design as the Helios RD series horizontal outlet roof fans, ensuring a uniform aesthetic in rooftop installations. Constructed for both natural and mechanical ventilation applications, the unit provides effective weather protection. When integrated into mechanically ventilated systems, flow losses should be considered, as illustrated in the corresponding technical diagrams.