EF-4 Filter:- One-piece effluent filter fits in 4" sanitary tee- Injection molded PolyPro- Simple to install - Easy to clean18 Per Carton4" Sanitary Inlet/Outlet T Baffle™- Injection molded T-Baffle- Fits 4" Sch40 and SDR-35 pipe- Simple to install- May also be used as Inlet and Outlet Tee18 Per CartonEF-4COMBO - Includes one EF-4 Filter and one 4" Sanitary Inlet/Outlet T-Baffle18 Per CartonSD-4 - Sold Seperately- Gas/Solids Deflector- Increases time between filter cleaning