The Rheem AS38923 Draft Diverter Vent Hood is designed for 3" or 4" vent pipes, ensuring optimal draft control and venting efficiency. Engineered to prevent backdrafts and protect your system from external elements, this durable vent hood enhances the safety and performance of your heating setup. Its robust construction supports reliable operation in various conditions, making it an essential component for maintaining proper ventilation in residential or commercial applications.