[Material]Pipe draft exhaust fan is made of quality pp material,which is durable and sturdy,can be used for a long time [Design] 1.When the exhaust starts,the air pressure pushes the butterfly valve to open,and odor and exhaust is quickly discharged.2.After the exhaust is completed,the pipeline valve will automatically close under the action of for gravity [Multifunction]The check valve will always remain closed to prevent the exhaust,dust and odor from entering the room [Feature]The backdraft damper keeps odors and exhaust gases out of the house,prevent backflow [Fine Workmanship]Practical pipe check valve can be closely attached to the wall,no leakage,and ensure good sealing performance, Weight: 0.1212542441 Pounds, Manufacturer: QLECXZI