Safety Technology International, Inc. STI-3360 Wireless Entry Alert Chime with Receiver, Door or Window Transmitter Sensor STI-3353 Receiver Sold Separately Entrance alert notifies when connection is opened for example a door, window or cabinet is opened Quick and easy to install no wiring needed Operates up to 500 feet (line of sight) Receiver has low and high volume adjustment and ten selectable sound options UL & CUL Listed, FCC & IC Compliant. Limited one year warranty.