Prior to the official announcement of the Apple Watch, there were multiple rumors that the device would be packed with health-related sensors. When it finally launched, however, it got just a heart-rate monitor – albeit a sophisticated one. A teardown revealed that there’s also a pulse oximeter in there, to measure oxygen saturation in your blood, but Apple hasn’t yet activated that functionality.

The apparent turnabout on sensors was explained by Tim Cook, who last year told the Telegraph that Apple wanted to avoid the need for FDA approval as a regulated health product as that would slow innovation. Any additional sensors, he strongly hinted, would be external.

If you don’t want to wait that long, however, health-tech company Azoi has launched the Kito+, a credit-card sized unit that pairs with an iPhone app to measure heart-rate, ECG, blood oxygen, respiration rate and skin temperature. Costing £99 ($145), you can either use it as a standalone unit, or slot it into the supplied iPhone case for the iPhone 6/6s/Plus …

Azio is at pains to point out that the Kito+ is not a substitute for professional medical diagnostic equipment, and makes relatively modest claims for its accuracy. Heart-rate is +/- 10% or 5bpm, whichever is the greater; O2 saturation is +/- 3.5%; respiration is +/- 3 breaths per minute. Only skin temperature achieves any real precision, accurate to within 0.3C.

It’s also notable that, although Azio is based in California, it’s only officially on sale in the UK as yet. That’s because it’s still going through FDA approvals, which the company expects to take a few months.

I’d say this is something you need to view as providing the broad brush-strokes for someone interested in monitoring their general health, and perhaps providing an early indicator of issues that should be properly investigated.

Look & feel

At 97x53x3.4mm, the Kito+ itself is a little longer and narrower than a credit card, and as thick as four stacked cards. It weighs 20g.

It’s made of the ubiquitous ABS plastic, though with a rather pleasant feel to the finish. Embedded are two large metal sensors used for ECG and heart-rate, a small metal one for skin temp and a clear window for the pulse-oximeter used to measure both O2 saturation and respiration rate. You power it on by pressing a near-invisible black power button, at which point a white LED comes on.

There’s also a recessed charging port. A separate dongle snaps magnetically into this, providing a micro-USB port for charging. This approach keeps the unit itself as slim as possible, but does mean there’s an extra (and rather small) dongle to lose.

The supplied iPhone cases for 6/6s/Plus are semi-rigid rubber ones. They’re not going to win any design awards, but are inoffensive enough. Since iPhone and Android owners pay the same price, and only iPhone owners get the cases, you can view them as freebies. Since I switched to the iPhone SE, I just used the Kito+ in standalone mode.


Setup is straightforward. You download the companion app which asks for your email address and a password, then your date of birth, gender, height and weight.

One nice touch is that the app auto-pairs with the device without any need to go into the Settings app to do the Bluetooth pairing. More manufacturers should take this approach.


You power-on the device by pressing the power button, and then press the Check-Up button in the app. But give it a few seconds between the two to pair, or you’ll get an error message.

Once I’d used it a couple of times, I realised that the app button turns solid orange when it’s ready.

The app shows you how to hold the unit.

That screen displays for a few seconds. You can touch the screen to skip it, but of course have to remove your fingers from the device to do that. It would be better if it detected your fingers and then auto-started.

Measurements take 30 seconds, and it displays live data for ECG, heart-rate, O2 sat and skin temperature as it runs.

Afterwards, it displays a summary of all the data, and you can tap each item to see more details.

Most items just show you a graph of most recent and earlier readings, while the ECG presents a scrollable image.

However, the app gives no clue what any of the data means. It doesn’t give any indication of normal ranges, and deliberately taking just one breath during a measurement (to see if anything abnormal would trigger an alert) didn’t do anything. To discover what the normal ranges were for each, I had to do a fair bit of Googling.


The unit is neat, portable and easy to use. Providing ECG readings (which measure the electrical signals controlling the heart, and can indicate the state of your cardiac health) is a significant step up from simple heart-rate readings.

However, unless you have medical training, or are prepared to do a fair bit of research, you are presented with a bunch of data with no clue whether it is good, bad or indifferent. This seems particularly odd given that it captures base data (age, weight and so on) that you would think was collected in order to interpret the readings.

I’m probably not the target market. I’d imagine most of those buying this will be either those with known health issues, massively into fitness – or hypochondriacs. I don’t fall into either of the former categories, and am about as far from the latter as you could get (I once went five days without realizing I’d broken my elbow).

The limited accuracy also makes me question the usefulness. The stated accuracy isn’t terrible, but it’s not great either. I did a few comparisons of respiration rate against manual counts, and it was out by 2-3 breaths each time. I also compared the heart rate against my Apple Watch, and the two varied by between two and four beats per minute.

But as a gadget, it’s impressive. Just the idea of a consumer-priced ECG machine is something that would have been hard to imagine just a few years ago. Those into health and fitness in a big way will likely know what the readings mean for them, and maybe the inaccuracies will average out over time.

Kito+ is currently only on sale in the UK from Azoi’s website, priced at £99 ($145).