Trolmaster Dry Contact Station Wall Fans & Others This Easy To Use Co2 This Easy To Use Co2 Controller Determines Precisely When To Activate And Shut Off Co2 Generators To Maintain User Defined Low And High Co2 Values In The Grow Room The Unit Can Deactivate Co2 Enrichment During The Night Cycle And Perform Co2 Cuttings grown in Preforma produce notably cleaner callous than in other propagation substrates Some equipment requires either normally open or normally closed contact closure in order to activate the equipment The DSD 1 plugs into a standard Nema 120 volt 15 20 amp power outlet to provide operating power to the DSD 1 circuitry