This baptistry pool alarm can be used as an extra layer of defense to keep children safe. An alarm sounds at the pool and in a remote mounted location up to 200ft away. Remote receiver features and on/off switch and runs on 110ac. Floating pool alarm runs on 9v battery (not included). If a child falls in the baptistry, the wave activates the floating sensor and sounds the alarm. WARNING: Do not rely on an alarm as your only measure of safety. Filled baptistries should also have physical restraints in place, (locked doors, gates, solid covers, etc.) to physically keep children from approaching the baptistry.