WITT non-return valves protect plants, pipelines and outlet points against reverse gasflow and meet all relevant standards and regulations. The product range of non-return valves includes a large choice of nominal sizes (up to DN200) and flow rates (0.35 &ndash 106 SCFH). The sophisticated valve technology of WITT non-return valves provides small pressure drops making them also suitable for applications with smallest opening pressures. A high-quality sealing system with elastomeres prevents leakages and dirt filters at the inlet point assure long service life of the non-return valves. Some non-return valve models can also be used as flashback arrestors. All non-return valves can be mounted in any orientation, are available with all connections, in brass and stainless steel and are suitable for almost all technical gases.