Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Expensive recalibration required!

According the the manufacturer, this device requires periodic re-calibration which can only be done, feasibly, by the company. Re-calibration costs approximately 40% of the purchase price and these facts should have been prominently disclosed in the item description! Now I'm stuck with a 15% re-stocking fee plus return postage. Not a good experience.