Universal Low Voltage Alarm For Use With The Following Diversitech Products, Wet Switch, SOS, Condensate Cop, CP-22(All Types) And All Float Switches On 24VAC Control Circuits, 2 Wire Connection For Easy Hook Up, Includes Lable To Print Contactor Call Back Service Information, Actuates At Greater Than 18 Volt To Prevent Low Voltage False Alarm, Low Current Draw, Dims:2-1/2"H x 2"W x 3/4"D, Origin:China