... well Buzzer alarm Alarm starts when VOC value above 25ppm LCD backlit Green—optimal air quality ► enjoy the air quality Orange ... VOC-B320A IAQ, temperature and humidity monitor/alarm Three-color backlit LCD, buzzer alarm 230VAC Wall mounting G02-VOC-B332C IAQ, ... VOC-B310A IAQ, temperature and humidity monitor/alarm Three-color backlit LCD, buzzer alarm. Modbus RS485 interface 230VAC Wall mounting G02- ...