CO2 Monitor & Controller. CO2 Monitor Controller Model # 2002A and 2002B by Control Wizard Products. These two units work together to give outstanding results and value to the customer. They can be purchased seperately, see product number CO 350 and CO 351.This combo has been designed to turn CO2 equipment ON and OFF at preset levels by reading the Monitors signal output. Simply plug in your CO2 equipment i... — Ships from Portland, Oregon USA — Free Shipping when ordering $50 or more of qualifying items....more info.