Used in conjunction with the O₂ controller, the Coy CO₂ controller allows for precise control and constant digital monitoring of CO₂ gas inside the cabinet. The controller compares the measured CO₂ level to a user-defined set point and controls the introduction of N₂ or CO₂ gas into the cabinet. The digital display allows the user to continuously monitor the cabinet CO₂ level and adjust level from 0-20% in 0.1% increments. Unlike other systems, this dual controller approach allows simultaneous bi-directional control of O₂ and CO₂, which is important since an adjustment in one has can affect the level of the other. The digital display allows the user to monitor the CO₂ levels constantly for 0-20% control in 0.1% increments.