From their website;
Xiaomi has unveiled its second-generation fitness tracker in China over the weekend, the Mi Band Pulse. Set to go on sale on November 11 — or Singles’ Day — the tracker comes with an optical heart rate sensor, retaining a design that’s similar to its predecessor.
The Mi Band Pulse shares the $15 (99 Yuan) asking price as the first-gen model, making it one of the most affordable fitness trackers available today. The addition of the heart rate sensor means that it now offers a more comprehensive activity tracking solution, which includes steps tracking, calorie intake and quality of sleep.