I used the oral therm as my 'standard' to test the therms I would use in the bator.
Used a candy therm to get a cup of tap water to about 100F,
then immersed oral and bator therms in the water.
Noted differences of the bator therms to adjust my readings.
The bator therms were 1-6 degrees off.
This is an incubator therm from little giant,
it is mounted on clear acetate so it sits on top of the eggs.
Note that it says right on there to test against a known accurate therm.
Not a great pic, but circled is where I noted the difference.
View attachment 1141604
ETA: I was using a buddies bator, they had bad hatches.
Found the therm in lid was off by 6 degrees,
therm was clearly marked 'for reference only'.
I wonder about those glued to the card. The lines are on the card, not on the glass, so if it gets glued in the wrong place, it's off.