The PS-1 Photostat is used to turn equipment “Off” during a photo “Off” period (night operation). When the lights are “Off” the control equipment will be powered down. In this mode the Photostat is ideal for use in CO2 generation. The Photostat may also be used to turn equipment “Off” during a photo “On” period (Daylight Operation). Switch between day or night operation. The PS-1 can also be used to operate indoor or supplementary lighting to correspond to natural outdoor daylight hours as seasons change. In DAY mode locate the PS-1 so it detects outdoor day length and functions your indoor lighting timer accordingly.