Keep your children safe with the Techko S187D Safe Pool Alarm. This alarm monitors gates, doors, windows, and any other entryway to your pool. The alarm is compliant with UL 2017 safety standards & is designed to be kept out of reach of children, so you will be alerted whenever the pool is accessed. * * The alarm features a high-output 110 decibel alarm siren that sounds whenever the magnetic contact is broken. Adults can easily enter/exit from both sides by using the two included bypass buttons, temporarily disabling the alarm for 10 seconds. * * This alarm also features a patented secondary sensor, designed to be used with sliding doors that have a complementary screen door. When secondary sensor is installed, the alarm will only trigger when both the screen & glass doors are opened, allowing you to keep your glass door propped open to let in the breeze. * * (Please note that the secondary sensor cannot be used to double up as an additional alarm another entry point, ie. you will need one alarm per door/window) * * This alarm is certified by ETL, a 3rd-party testing lab, and is approved under UL 2017 standards for pool inspections.