KOBOLD LPS air flow switches are widely used to control air flow setpoints in HVAC duct applications. The principle of operation is quite simple. Air flow exerts a force on a paddle, actuating a dust-tight SPDT micro switch. The switching point may be adjusted continuously within a wide range, making the LPS useful in a wide variety of applications. The LPS paddle-wheel air flow switch is factory set to switch at 195 FPM. To handle air velocities greater than 920 FPM, the paddle may be cut at a precalibrated mark. This automatically changes the factory setpoint to 490 FPM.