Pre-Set Co2 System Controller Use With S, M & L Deluxe ChambersPre Set CO2 System 1 Chamber S S Housing A product very similar to our already popular Auto CO2 Delivery Unit but without the need for calculating chamber volumes to obtain the correct CO2 concentration. This system has 3 pre set settings. Each of the settings is calculated for use with one of our small, medium or large CO2 chambers. Simple operation Automatically provides a 20% rising concentration. No discrepancy between procedures Simple wall mount