ok cool...'cause i just upgraded from a little rinky dink zilla digital thermo/hygrometer and found out that the temps were like 4.5 degrees off and when i had low humidity it was actually high and it had 2 probes with suction cups on each one, measuring the temp and the other measuring humidity but with this acu-rite i didnt know it measured both sides at the same time..its a nice investment i recommend acu-rite to anyone over those pet store "toys"