Complete your home security plans with the Steren door and window security alarm. It is activated when the magnetic counter is separated from the main component. This alarm has a three position switch: warning, alarm and off. It has a 100 foot 90dB ton range and is powered by 4.5Vcc (3 button cells). Measurements: alarm box (2.52” x 1.18” x 1”), magnetic box (0.5”, x 2.09” x 0.59”). It is recommended to use with the Steren Security Door/Window Magnetic Sensor (ALA-005).