The Cycle Timer controls any 120V equipment such as irrigation pumps, fogger, fans or CO2 generators on periodic cycles. The output is repeatedly turned ON and OFF for periods corresponding to the ON and OFF times. On time from 1 to 60 minutes. Off time from 5 minutes to 12 hours. 3 position slide switch: Day-Day cycle only, 24 Hour Day and Night cycles and Night-Night cycle only.