Glass Break Detector Transmitter Operating Frequency 320.000 MHz Transmission Range 500 ft Compatible With Napco Receivers Powered By (2) CR123A Batteries For Use With Napco Receivers Operating Temp Range 23 Degrees to 131 Degrees F Humidity Range 5 to 90 Percent Battery Life 3 yr Height 1.9 in Diameter 4 5/8 in Features Two Stage Detector Circuit Includes Screws