This is our popular Mini LCD Thermometer Hygrometer, a Digital Humidity Temperature meter with Probe/Sensor 

(Probe is designed to use in air. see digital thermometer below if measuring water/media/soil/air temps)

Use in Propagators to keep humidity above 60% and temps between 20 and 25 degrees*

Use in Grow rooms to keep humidity between 40-60% and temperature below 30 degrees and above 20 degrees.*

The Colour may be white or black due to availability.

*This is just a guide, and more of a beginners starting point - in extremely high light levels and advanced growing systems more humidity may or may not be needed and if not sufficiently skilled please get more guidance from our team. High humidity can lead to fungal infections as well as mildews. Check daily if propagators are very humid and release stale air each day, then rehumidify with a sprayer. Use defuse, silcia spray, or other fungicides to reduce infections if prone to them.

Does NOT include batteries. It takes 2 LR44 Button batteries to operate

Find them here: https://www.hydrocentre.com.au/batteries-for-pen-type-testers-single-battery-ag13