This is not suitable for placing inside an incubator, but is a cheap way to keep an eye on ambient humidity in the bird room, greenhouse or even outside. At the end of the day it is $16 so the accuracy is not going to be pin point, (and if you want something particularly accurate then look at the Button Digital Hygrometer), but we have used these successfully ourselves for several years to keep aneye on what is going on in the bird room and have had no complaints.  It’s not as if there is much to go wrong with them!