Window/Door Sensor Wireless Transmitter - Unique alarm transmitter made by Quorum contains a built in reed switch, and electronic intruder detection circuit with a built in RF transmitter, and an enclosed permanent magnet. Unit operates from a 9V battery (the one inside the box is dead from storage) and was meant to transmit a 433MHz signal to a receiver . Beige case is about 4 1/2"L X 1 1/2"W X 1" Dia. Brand new with mounting hardware included. Model AS-103 RR-150. High quality unit, perfect for alarm applications. G4568