Exit Door Alarm, Cylinder Type Key Lock, Alarm Type Horn, Siren Style Three Minute Piercing Horn, Activated By Unauthorized Egress, Alarm Duration 30 sec, 3 min or Continuously, Door Handing Non-Handed, Body Thickness 2 in, Body Dia. 5 in, Decibels 95 to 105dB, Power Source 9V Battery, Housing Material Polycarbonate, For Use With Double Exit and Entry Doors, Includes 9V Battery and Double Reed Switch Assembly, Door Alarm, Mounting Hardware