The Mercury 3 - Day/Night Fan Speed controller provides the indoor gardener with perfect ventilation control. Easy to use because it allows user to adjust dead-band range to meet gardens requirement. Just plug your fan into the controller, set the day and night temperature required for your garden, and then let the Mercury 3 do the rest of the work for you. Temperature control range is 55°F to 95°F and includes a 6 foot temperature probe that is accurate to within 2°F. 6 Amps/120 Volts/60 Hz. 3 year warranty included.