If I could give it no stars, I would.
I tried two of these thermometers...TWO. They are nearly impossible to shake down and even more difficult to read, as the blue line is the same color as the background line. Fortunately, Fairhaven's customer service policy is generous. They sent me a replacement after the first, a digital thermometer after the second, and finally a refund when all three thermometers failed to work.
Merchant Response:Hi Jenn: So sorry to hear of the repeated troubles w/the basal thermometer. Galinstan, which is the substance that's used instead of mercury in this thermometer, is a bit more temperamental than the mercury that many of us grew up with. In particular, it is temperature sensitive. As such, it should be washed with lukewarm water rather than hot water. When you use hot water, the galinstan can sort of lock into position for a period of time, which I believe is what happened to you. In any case, our apologies for the inconvenience here, and all the best to you!