I don't trust oscillometric blood pressure monitors. They simply are not accurate regardless of manufacturer claims. These are the units that determine your blood pressure by measuring the small pulsing of the air pressure in the arm cuff and represent the vast majority of units on the market. My previous unit was an oscillometric and I figured it would give a moderately accurate reading about once in every four measurements. My blood pressure is textbook 120/80 most of the time but the old monitor would often read it as 140/80 or even 150/80. For some reason it got the diastolic number correct pretty much all the time but the systolic number was a crap shoot. I used to verify the result by using a stethoscope like a doctor would: watching the pressure as the measurement was being taken. I could easily tell when it was way off mark.

OK long description but the bottom line is the Homedics unit with the microphone in the cuff is 100% accurate all the time. When I first bought it I used my stethoscope in conjunction with it as I did my old monitor. I found every single measurement to be accurate without exception. I now trust it completely and don't use the stethoscope anymore. I highly recommend this product. It is top-of-the-line.