The Wireless Alert Series wirelessly monitors up to 4 different STI devices at a single, convenient location. When the included 4-Channel Voice Receiver detects a tripped site, it sounds programmable voice messages to alert which transmitter has been activated. The receiver offers ten tones/tunes and 53 selectable words (available in English or Spanish). Supervised for low battery and signal reception, it operates up to 1000’ (line of sight). Monitors - open/closed garage door, mail delivery, car in the driveway, fence gate, medicine cabinet, indoor or outdoor area, etc.