Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A Scale that Can't Measure

I bought this scale because it measured in troy ounces. When I received it I read all the instructions and grabbed a 1oz silver coin to test the scale out. It read below half an oz. I thought this was odd so I took it into work the next day to compare it to one of our calibrated test scales. At first I just thought that the scale needed to be calibrated. So I followed the instructions on calibrating it. After the calibration I again made some measurements using the calibrated test scale for comparison. I measured exactly 500.0g using the calibrated test scale but everytime I placed the weight on the AWS scale I got a different measurement. Once it read 507.9g. I took the weight off, waited for the scale to show 0.0g, then placed the weight back on and got 467.7g. I cannot trust this scale, not worth buying.