Lasso Technik AG is a Swiss family-owned company based in Basel, founded in 1942. Its core activity includes the development, manufacture and distribution of valves under the Stop Silent® brand. The range is divided into two product lines: The Stop Silent® SL13 check valves protect against backflow of fecal-containing wastewater and serve as a barrier against radon and sewer gases. The Stop Silent® AS backflow valves prevent backflow in drinking water and industrial facilities. Lasso Technik supplies customers at home and abroad and also develops customized solutions.