The STI-V34700 Wireless Indoor Motion Detector Alert lets you know when the sensor detects movement in a monitored area. When motion is detected, the device sends a wireless radio signal to the indoor voice receiver display, operates up to 1000' (line of sight), which will sound a tone/tune or programmable voice message letting you know someone has arrived. If the supervised transmitter is removed from the door, stolen, loses signal or battery is low, the receiver will produce a single beep once a minute. Sensor uses one 3 volt lithium battery (included), with an average life of 5 years in normal use. To conserve battery, when sensor is tripped it will not activate for three minutes.
Everything you need to know about the STI 4-Channel Voice Receiver