MOBIAK WET ALARM VALVE is UL Listed & FM approved. The wet alarm valve is designed for applications where the water is unlikely to freeze. The water staying pressurized in the pipes is released over the fire area after the sprinkler is activated due to fire. The pressurized water system is not only fed continuously, but also fills in the retard chamber. After the chamber is filled, the pressure switch on the chamber is actuated. The pressure switch sends the alarm information to the fire warning system or the automation system. After the pressure switch is actuated, the water is delivered to the water-motor gong and releases a mechanical alarm.