... parts 2, Suitable for variable diameter demands 3, Extremely low pressure loss 4, Easy installation Electronic flow switch (Thermal differential type) ... flow velocity .Feature1,No movable parts . 2, Maintenance free. 3,Easy installation. 4,Suitable for variable diameter demand . 5, Switching value can ... idle .Technical data set range :1…150cm/s(water), 3…300cm/s(oil),20…2000cm/s(air)Output: PNP, ...