Title: Dies after 20 minutes
Review: The Zen Stone worked fine for the first two weeks. But then it started turning off after about 20 minutes of use. It could not be restarted immediately. I returned it to the store and got another. But the new one did the exact same thing on its first day of use. I think it may have to do with being out in the cold. When it worked for the first two weeks, temperatures were still in the 50's or above. The problem seems to occur when temperatures are below around 45 degrees. I would not recommend it if you plan to use it outside in cold weather.
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