HDF Pumps are recommended for abrasive slurries, suspended and non-suspended solids and line-size solids. All SANDPIPER® Heavy Duty Flap Pumps are configured with bottom discharge porting to prevent settling solids from shortening pump life and provide superior suction lift. HDF2 pumps are thick wall constructed of Sand Casted Aluminum, Cast Iron and Stainless Steel with elastomer and TPE (thermal plastic elastomer) diaphragms and check valves. See tabs below for a complete description.