I bought this monitor it based on positive feedback .... I'm not entirely satisfied with this unit as the measures taken at one time are not reliable. Major differences, for example one minute to the next, ranging from 10/5 to 13/8 'which is completely crazy. The worst is when the unit displays 17/9 while in reality the voltage to around 13 or 14 .... Is it the fact to fix badly the unit on the wrist? I do not really think. Besides this device is not intended for people with end wrist and even less for teenagers or children who may need a plug occasional or lasting tension ... I fortunately have the chance to have a Braun with both cuffs for arms purposes and stronger, and that is by comparing the voltage taps I noticed these huge difference measurements. Sometimes this blood pressure monitor Beurer takes the trouble to indicate a substantially normal voltage but then you try three or four times in a row .... Attempts who never occur with another monitor. I do not recommend this at all for people having only one blood pressure monitor at home and could thus run the danger of relying on the first try to measure indications. Unless dropped by serendipitously on a device that would not fault that I just mentioned ... Better pay a bit more and have a reliable product.