Sunleaves LARGE Display Hygro-Thermometer 

Keep track of humidity and temperature readings at a glance with a Sunleaves' large display Hygro-Thermometer. The digital numbers are big enough that you can easily read them from across the room! 

Display temperature in either Centigrade or Fahrenheit - your choice. Place on a flat surface using the built-in foldaway stand, or mount on the wall, or grow room surface using the precut keyhole or Velcro tape.

The Hygro-Thermometer includes a remote probe for a second zone temperature reading that's great for monitoring inside domed growing trays! Or set it outside the house for outdoor readings.

This handy device records the high and low points for both the temperature and humidity to help fine-tune your grow room accuracy.

More info from the Manufacturer (PDF format - Lots of detail.)