From the product description, check product page for current description, price and availability:

• NOTE — To protect heating and cooling device, we designed that the min temperature range from Heating Set Point(or Cooling Set Point) to Stop Value is 6℉/3℃. It’ because, if the differential is set too less, it will cause frequent startup and shutdown of the device.
• Keep Ideal Temperature — The thermostat provides constant optimal temperatures, and keeps your environment in the ideal temperature range.
• Heating & Cooling Mode — Dual relay output, allow control heating and refrigeration equipment at the same time.
• Convenient Design — Plug and play design. The large, lighted LCD screen display is easy to read and program. Support reading with Centigrade and Fahrenheit unit. Handheld device appearance consistent with the principles of ergonomics.
• Widely Applied — The thermostat can be used to control a wide variety of dual-stage refrigeration and heating, HVAC equipment, fermentation, grow tent, home brewing, aquarium, incubation and BBQ, etc.