The Runxin F56A1 manual backwash valve can be used on several different FRP vessels including with medias such as Silica sand, Activated carbon, Glass, Birm, Calcite and others as long as the vessel has a 2.5” top opening. The backwash valve allows you to wash out all the trapped dirt, rust or other particles trapped between the grains of media and will also re-set and re-compact the media bed to prevent and remedy channeling. The backwash valve uses a manual handle that can be turned (much like a swimming pool filter) to backwash and fast-rinse your filter vessel. The ports on the valve are all 1” (25mm) female threaded ports to connect to a variety of fittings and supports a maximum flow of 4500L/h.