KARMAT Backwater Valves (non-return valves) effectively secure any rooms located on the lower floors against flooding caused by back flow of storm water and sewage. Back flow may be caused by intense rains, thaw or floods. Use of anti-flooding devices for rooms located on the lower floors is required by obligatory regulations related to technical conditions that are to be satisfied by building codes - Diameter: 200mm; - Mounting: horizontal; - Made of a durable and high quality polipropylene; - Resistant to corrosion, negative temperatures and chemicals; - Simple and effective closure mechanisim; - Easy to install; - Self operating without the need of external power; - Effective rodent protection; - Inhibits unpleasant smells from reentering; - The flap guard, as well as all assembly elements (screws, nuts, washers) are made from corrosion resistant chromium nickel; - Eequipped with a manual closure lever; - Changing of the lever from OPEN position A to CLOSED position B causes a