Xiaomi Band 4

Xiaomi make everything or they invest in other companies to make stuff for them. If you want something for the home, there will be a Xiaomi (or more likely under the Mi brand) product available. An electric toothbrush, yes, a pen (called a signing pen), yes. Lighting, yes, speakers, smart speakers, humidifiers, air purifiers, air quality sensors.

Some of the products are available directly in the UK (there's even a Mi Store at Westfield in Shepherd's Bush), download the Mi Store app and set your country and you can order through the app.

However in the UK there's only a tiny subset of what Xiaomi actually sell, if you dare, head over to Aliexpress and search of Xiaomi or Mi and see the plethora of products available. Reign in your credit card as it's easy to just buy everything.

Amazfit are one of the companies that Xiaomi initially invested in (and now may well own, another is Segway/Ninebot). There's a previous review of the Amazfit Cor and though the screen is monochrome OLED, it's still quite a nice tracker. Unfortunately the strap eventually broke (which doesn't seem replaceable which seems a shame as the actual unit was working perfectly), so the to replace with a Mi Band 4.

Mi have regularly updated the band and it's very cost effective compared to the general (US) competition (Fitbit etc). It's not the prettiest of devices, the central "pod" (which is removed from the strap to charge) is about 4cm long by 1.5 cm wide and 1cm high. It has a colour AMOLED display and optical pulse/heart rate sensor on the base in contact with the skin. The strap is silicone and uses a pass through system and a knob that pushes into a hole on the other side.

The quoted battery life is 20 days, though this can reduce if certain settings are enabled (like heart rate read every minute and accurate sleep tracking etc), however it's still pretty reasonable with everything turned up to the max and won't need charging for several days at least. The band is also waterproof down to 50m (i.e. 5 ATM of pressure) so good for a swim in the pool or shower, but not recommended for deep sea divers.

There are lots of "watch faces" available (most are horrid) and if you're an Android/Windows user, then are are sites that show how to design and install your own.

To get the data off the band it works with the Mi Fit app (which is available on both iOS and Android). All customisation is done through the app, though some can be done through settings on the band itself, though it's a bit fiddly.

It can all the normal things a tracker can i.e.

• Notifications
• Controlling Music
• Calls
• Steps
• Calories

There's also workouts that can be tracked" -

• Outdoor Running
• Treadmill
• Cycling
• Walking
• Freestyle
• Pool swimming

The band can also display the Weather.

On the band itself it's possible to set (under More): -

• Do Not Disturb (DND)
• Alarms
• Music
• Stopwatch
• Timer
• Find Device
• Band Display (brightness etc)

Everything works, heart rate tracking is as good as any optical sensor device can be as if you're doing sport and the band moved away from the skin, it's not going to measure properly. Sleep tracking works very well and shows speeds of awake, deep sleep and REM sleep.

The Official Mi UK price is £34.99 which is still pretty good for the features, however if waiting a few days and ordering from China isn't an issue that will significantly reduces the cost.