Everspring ST812 The ST812 is a battery-powered device, which is in sleeping state unless an action is detected. After a programmable sleeping time the device wakes up and sends a status information. After this the unit goes back to sleeping modus. Batteries can be changed without unscrewing the device from the door or frame. The unit will give a visual warning on the device and sends a warning to the Z-Wave controller, when batteries need to be replaced. Our Water/Flood Sensors can help give you early warning about water leaks or flood conditions. Responding to these conditions quickly can help prevent expensive water damage. The sensor is activated anytime the detector comes in contact with water.