Active relay for connection to remote or local alarm panel, fan or horn if there is a gas leak or to shut off a gas supply valve. Detects Methane or Propane. Calibration level is 20% of LEL for selected gas. Model HIC-813C has 3-wire connection: red for +12V DC in; Black for -12V DC and common; Green for alarm. Green wire is relay contact and is open to Common when either: no power, power with gas present (alarm state) or closed in ready state. Model HIC-813C/AN has 4-wire connection: red for +12V DC in Black for -12V DC and Common; Yellow and Blue for Alarm. Yellow becomes connected to Common when either there is no power to gas detector or there is power with gas present (alarm state). Blue wire completes circuit to Common of external solenoid valve. Will not complete circuit if there is no power to gas detector or there is power with gas present (alarm state). When circuit is not completed, solenoid valve will remain in closed position, cutting off gas supply to generator or supply power to turn solenoid on in ready state. The recommended area for one detector is10,000 cubic feet. 1-year limited warranty