Xiaomi's much-speculated second wearable device is now official, after the Chinese company unveiled the Mi Band Pulse.<br />A report from Canalys earlier this year speculated that the Mi Band, the company's debut wearable, made Xiaomi the world's second largest seller of wearables behind only Fitbit.<br />That was before the Apple Watch went on sale, of course, but this follow-up builds on that potential by adding more functionality.<br />That's because, beyond tracking your steps and sleep, alarms and some notifications, the Mi Band Pulse includes a heart rate tracker, as previously speculated.<br />Most importantly, the device has retained a low price tag.<br />That's 99 CNY, or around $15, this time around.