Innacurate readings, calibration is a joke. I’m a medical student with a pregnant wife who has had preeclampsia in the past, so I bought this to monitor her blood pressure. I took her blood pressure every day, and it was high, so I ended up taking her to the doctors. After an extensive work up, I compared this blood pressure cuff to the ones at the hospital, and this one was 15 mmhg too high. I tried their calibration tool, but it even says on the instructions included with the tool that it can only calibrate for differences up to 6 mmhg, less than half the difference I have. I ended up returning it and buying a Welch allyn one instead.