Air flow switch for monitoring air flows in ducts, in supply and exhaust air devices of fans or electrical heating registers. The air flow switch is set to the minimum switching points at the factory. The switch-on / switch-off values can be increased by turning the inner screw clockwise. Installation takes place in a vertical paddle position from above in a horizontal pipe / channel. The setting range is 2m / s… 9.2m / s and the hysteresis approx. 1m / s.