Flap valves of Karmat are innovative devices protecting rooms on the lower levels against flooding caused by backward flow of storm water and sewage. These devices are fully self-activating. Flap valves effectively protect plumbing systems from rats entering the buildings. Flap valves are installed at the end of sanitary sewage pipes entering collection wells, cesspits or drainage pipes leading storm water to ditches or rivers. Advantages: - high quality polypropylene and stainless steel ending; - sun light/high temperature resistance; - immunity to aggressive chemical compounds