Seco-Larm E-37EV Alarm Pager System, Monitors up to three zones per premises or vehicle, Manual Paging, 4W output, One Half Mile Range; Connect to nearly any type of burglar alarm control panel, vehicle alarm, communications panel, etc; One positive and two negative instant trigger inputs; Over two million possible coding combinations; Belt-clip receiver included; Code-learning receiver learns up to three transmitters; Color LEDs on the receiver indicate which zone (Green, Orange, or Red) of the premises or vehicle was triggered; Audible or vibration page indicator; EEPROM memory stores codes for up to one year without power; Stores the last six pages for easy recall; Unattended page indicator; Low battery indicator; Uses two AAA batteries (not included); Optinal Extra vibrating receiver available (E-37RV); Connect to a CB antenna, car AM radio antenna (cable included), or optional external antenna (E-37ANT).