The water weasel makes a huge difference in showing that the internal temps in an egg do not change as rapidly as the bator air temps so you aren't tempted to make any hasty adjustments. I just found one at the discount dollar store for $2. Called a water weiner or something equally stupid, LOL...
Me, too, Carole! You're overdue! Ironically, the hygrometer on that one is not accurate in larger spaces like a room, but much more on the money in an enclosed space. I calibrated it and the other one I have made by Springfield that is smaller I bought at Home Depot.
Carole, if you have the one I think you have, one reading is the outside temp and one is meant to be the inside temp. People put the probe outside a window to read that temp, so the probe will go into your water weasel or anywhere inside the bator and the one that is the "outside temp" is your...