The 2808 Absence of Water Sensor is a totally new innovative design that helps monitor the level of water and other non flammable liquids. The GRI 2808 is submersible, fully self-contained and responds reliably to the absence of or the presence of water. The sensor fits a multitude of applications in a wide range of environmental landscapes. The sensor microprocessor conducts a sample every 2.5 minutes. Optional custom sample rates are available. Call the factory for more information. The C-form relay gives the installer greater flexibility for triggering wireless and hardwired communication devices