Instruct: Classify an Amazon review into positive or negative sentiment.
Query: internally fragile

Within the first couple of weeks of using it as a tea thermometer, I found that tapping on the dial lightly will cause the needle to jump by up to 20 degrees. It still seems to work somewhat, but it's hard to really trust a thermometer that can be so easily convinced to adjust itself by 20 degrees one way or the other.As other reviewers have noted, it is also fairly slow, even in water (which conducts heat pretty well).