This one can be tricky
I read the instructions before using this the first time,  and I got a blood pressure reading of 150/106... that's not good.  I took it to my doctor and she recommended my arm differently, and I began getting readings that were more in line with what she was getting in her office.  I'm giving this three reviews because I was so frustrated initially,  but now that I know the tricks, it works well.
Rating: 3 stars