Advanced Irrigation Control with Flow Monitoring. With the ESP-ME3 Controller and Flow Sensor together, this will allow for convenient water management and accurate measurements at your fingertips on your smart phone with the Rain Bird Mobile App. Customer can now be proactive against leaks. The flow sensor can detect flow rates as low as 1.2 gallons per minute to 50 GPM. Flow monitoring and notifications will help save water and protect against any property damage.