I've never known a mercury (Style) thermometer to be off, but maybe I'm wrong. It also has a built in hygrometer, and it is $3 from Home Depot. Here is the link, the SKU# is 816799 in case the link doesnt work http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053
I have one of those on the wall. I went to the store, compared the temps reading on about 10 units, and picked one from the few that read the same. I too would not use it in an incubator. The "temperature" is as accurate as the person who glued on the glass with alcohol to the plastic backing.
