All pools should be fenced, but the weakest link in the fence is the gate and it should be alarmed. Any gate which allows young children easy access to a pool area should have a gate alarm. The Poolguard® Gate Alarm can be used on any gate, outside door or screen giving access to your pool. The alarm sounds in seven seconds if a child opens the gate, or even if they close the gate. The alarm is always on and always automatically resets under all conditions. It is equipped with an adult pass through feature that allows adults to go through the gate without the alarm sounding. The Gate Alarm uses one 9-volt battery, not included.