Sentinels Master Digital Timer combines the two main functions required for hydroponics into one convenient package. One side of the MDT-1 controls devices like submersible pumps, to control flood cycles, or drip systems. Watering times can be precisely controlled by day, night or 24 hours, and can be set in durations of hours, minutes or seconds. The other side of the MDT-1 can control lights and heating or cooling devices. This side is set up for "Day" devices and "Night" devices. Day devices would be your lighting, you can connect up to 1200 watts of HID lighting directly to the MDT-1. This receptacle has important built-in safety features including: Hi-Temp protection, this will disable the lighting devices if the temperature inside the growing area exceeds the maximum temperature set by the user, and Hot-Start prevention which monitors the incoming power and will disable the lighting in the event of a power failure, and fter a user adjustable time delay, the lights are permitted to restart. Night devices such as heaters, dehumidifiers, air conditioners, or exhaust fans would be controlled when the lights are off. Comes with a remote temperature probe that can be placed inside the growing area while the MDT-1 is outside the growing area.