Review on ORIA Wireless Digital Thermometer with 3 Remote Sensors: Indoor Outdoor Temperature Monitor for Home, Office, Bedroom - LCD Backlight, Hygrometer Humidity Gauge by Ray Reeltalk

I use this indoor grow so I can always check on the surroundings without having to climb into the tent. I keep the main unit in my office. I use two sensors and both are within one degree temp/% RH of the standalone hygrometers I also use. I love the fact that they can be snapped into place to keep them exactly where I want them depending on the size of the plant. The touch light on the main unit and the presence of multiple sensors is a great thing. Very effective, easy to use, and at around $30-$35, definitely recommend it.