The STI Wireless Entry Alert Chime Kit lets you know when a door opens. It greets visitors, customers or clients with music, and alerts you to their presence. Simply mount the small transmitter and magnet to any door, and plug the receiver into a standard electrical outlet. No wiring is required. When the monitored door is opened, contact between the magnet and transmitter is broken. The transmitter then sends a signal to the receiver, which alerts you with music. The Entry Alert Kit can also be used as an alarm by selecting the alarm sound with a switch on the transmitter. Multiple receivers (additional sold separately) can be placed in multiple rooms up to 250 feet away from the transmitter. You can distinguish between front and back doors by adding more transmitters and programming a different tune on each. There are 13 sounds that can be selected with the push of a button on each transmitter. For security, there are 32 individual codes to protect against outside interference. Batteries included. CHIME OPTIONS: Ding, Ding Dong, Westminster Chime, Star Spangled Banner, Hail! Hail! The Gang"s All Here, Jingle Bells, Auld Lang Syne, Dixie, The Yellow Rose of Texas, Happy Birthday, Beethoven"s 5th, Joy To The World, Take Me Out To The Ballgame. CONTENTS: Chime Transmitter, Chime Receiver, 6 volt alkaline batteries (installed), Magnet, Double-sided tape, Screws.