Microsoft's wearable device.
Microsoft Band
Microsoft Band tracks your heart rate, steps, calorie burn and sleep quality with advanced, highly innovative sensors. It also helps you be more productive with email previews and calendar alerts at a glance.
Microsoft Band 2
Adds UV and barometer sensors.
Microsoft Band SDK
The Microsoft Band SDK gives developers access to the sensors available on the band, as well as the ability to create and send notifications to tiles. Enables Windows Phone 10 Universal Apps to handle tile events in the background. Enhance and extend the experience of your applications to your customers' wrists.
Microsoft Band SDK Download: http://developer.microsoftband.com/