The switch of the 3 way unit has an alarm setting, an off setting and a chime setting. When set, the chime setting allows you to hear a single pleasant tone when a door or window is opened. It's similar to the systems used in some retail stores. Like an automatic doorbell, it let's you know that someone has just triggered the alarm
Includes 4 First Alert Alarms with Batteries for Each Unit; Instructions
Item# : SPM9989942720
Model # : B0006B7M3Q