Most people are slightly vague on the functions provided by this relay and the important role it plays in the co-ordination of the total environment control system. Our Atmospheric Controllers function heaters, fans, coolers etc.. Timers control light cycles, irrigation and CO2 equipment. A switching control is needed to turn some functions "Off" while others operate and to disable some while others remain in service. Generally we want atmospheric control all 24 hours but we want CO2 enrichment during photo-periods only. The IR-1 will do this. It will also trigger the reset feature of the CST-1 and defeat CO2 during exhaust functions. Operates on 115VAC with 12 Amp switching capacity.Approved for indoor use only.