Green Air Cyclestat 4P repeat cycle timer with switchable photo sensor. REPEAT CYCLE TIMER WITH SWITCHABLE PHOTOSENSOR. The Cyclestat 4P repeat cycle timer optimizes accurate short cycle timing. Perfect for plant zone environments, reptile habitats or any other application requiring automatic short cycle switching. No programming required. Easy to set and operate. Microprocessor time counter with adjustable frequency and duration. The Cyclestat 4P timer has many uses. Only a few of them include: fogging or misting, spray stakes or drip system timing, air pumps, CO2 equipment and intake or exhaust fan control. The Cyclestat may be set for interval and cycle of timed events. Interval is the time between the On and Off cycles. The interval knob may be set from 5 minutes to 8 hours. Set this for desired time between functions. Cycle is the length of time that a specific function or condition must be maintained. Cycle may be set from 5 seconds to 30 minutes.