Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Disappointing

I believe that the wrist monitor shipped to me is defective. I intend to return it today. If the monitor worked as advertised, I would be quite satisfied with the features and design. The unit gave very low blood pressure readings as compared to an arm monitor by Omron that I have owned for years. I made an appointment with our family doctor that confirmed the low results. A call to Omron and the customer rep said that the results should be within 3 points of an my arm monitor. My results vary from 10 to 20 points lower on the systolic reading. Also, the LED readout is hard to discern. The numbers should be black, but appear to be dark gray. It is likely that I just received a defective machine.