Mcdonnell & miller for general purpose applications where high sensitivity is required and moderate or low flow rates are encountered such as air conditioning, heating and hydronic systems, water, fuel oil, some viscous liquids and oils in process work. In-line configuration eliminates need for a pipe tee. High flow capacity. 1/2in npt. Single pole, double throw snap switch. Switch compartment is completely sealed to protect it from the liquid. Sensitivity adjusting screw makes flow adjustment easy. Optional features – bspt threads – gold plated contacts. Minimum temperature fluid or ambient 32f 0c. Maximum temperature 225f 107c. Maximum operating pressure 100 psi 7 kg/cm2. .