> The Hilo Band uses photoplethysmography (PPG)—an optical sensor technology that collects data from your wrist. This data is sent securely through the Hilo App to Hilo’s cloud server, where advanced algorithms estimate your blood pressure using Pulse Wave Analysis (PWA), which looks beyond just the rate of your pulse, and examines the unique form of each heartbeat’s pressure through your blood vessels.

I doubt that it’s comparable to real blood pressure monitor.

I can do 3 cuff readings within 5 minutes are easily get +- 10 for each measurement. So it doesn't have to be super precise to have comparable accuracy to a cuff. Also the fact it is making continuous readings (even while asleep) is very helpful.

By "cuff" you mean the brachial artery ones, right? I'd be interested in both accuracy (same value when measuring the same thing) and precision (how close to actual value).

>By "cuff" you mean the brachial artery ones, right?

Yes, the one that goes on your bicep.

Anecodtally, it seems to be within the variance of the cuff (plus or minus 10).

Trying to measure both at the same time is tricky as you can't actually tell the Hilo device when to make a measurement. It does it on it's own scedule.

You are supposed to calibrate the bracelet against a cuff at least once a month.

It seems pretty consistent with a cuff. Also it doesn't jump around wildly from one minute to the next.

How comfortable is it? Do you have to wear it particularly tightly around your wrist or can you let it hang a little loose like a watch?

it doesn't need to be tight. I have it similar tightness to a watch. I don't really notice it. it is supposed to be waterproof, but I haven't really put that to the test.

I've had it a couple of weeks now. it is very convenient. However I am starting to notice some sizeable discrepancies with my pressure cuff. :0(