If you need to keep track of your blood pressure over time this is a great unit. You need to download a phone app which will store all your readings so that you or your doctor can review them at any time. Also has a visitor mode if someone else wants to use it without storing their readings with yours. If you have trouble with it not working its probably because the cuff is too tight on your arm. Just loosen it slightly and try again. After a few uses you know how tight to make the cuff.