TrolMaster CO2 Alarm Station w/ LEDThe AS 2 CO2 Alarm Station is an audible visual alarm module that features a color coded LED display indicator and a LCD digital ppm level display. It is designed to be mounted outside of grow room or grow facilities to monitor the CO2 ppm level. The AS 2 can be linked to either AL 1or AL 2 CO2 sensors channel, or it can be linked to both sensor channels for complete redundancy. The green LED indicator shows the CO2 level is below 800ppm which means