Features:Detects continuous or intermittent liquid flow with a loud beeper and flashing LED.Loud beeping cuts through the loudest industrial noise.Suitable for corrosive chemicals. Polypropylene housing, monel spring.Convenient test button to check function.Detects power failures with battery when 24/7 flow is required.Suited for pulsing flow from diaphragm pumps.Convenient pass-through receptacle.When there is an alarm, the push-button can be pressed to temporarily silence the alarm. An optional snooze-alarm feature sounds the alarm again after 30 mins.Test button where there is no active alarm.Power failure alarm built in.There is no real upper limit to the maximum flow except that it is a 3/4" NPT pipe fittings.Reversible logic so it detects either presence of flow or lack of flow.Low battery alarm.The flow switch is polypropylene with a monel spring to push the shuttle so it can be mounted in any orientation.Flow switch fitting size is 3/4" NPT. Can be adapted to 1/2" using reducing bushings.Lithium battery included.10 feet of communications cable is standard.Using a shuttle switch that liquid pushes into position, the Flow Alarm can be configured for either intermittent flow which is suitable for either dosing pumps that dose occasionally, or continuous flow operations. Both modes of operation sense liquid using a magnetic shuttle switch that is pushed into position when liquid impinges on it. Both modes can detect flow or lack of flow. Both modes have a snooze alarm feature to temporarily silence the buzzer after an alarm.For pumps that must run 24/7 the Flow Alarm runs in a different mode that includes a power failure alarm so it alarms whenever there is flow. (or no flow) Again the shuttle switch detects the presence (or absence of) flow or an alarm is given. In addition, if there is a power failure, the Flow Alarm has a battery backup that sounds an alarm. If your pump plug is unplugged from the receptacle, an alarm is given.The Flow Alarm is energized by the power to the dosing pump connected through a piggyback plug. When power is present, it waits for 10 seconds for flow to become established, and then gives an alarm if flow isn't detected. The shuttle requires a peak flow of 300 ml per minute to activate.For pulsing flows, the circuit buffers the readings so fluctuations are filtered. If there is a continuous 10 seconds without ever hitting the minimum 300ml/min flow, then the unit responds. This way the unit can detect average flow of less than 300ml as long as there are spikes over 300ml/min.