Made by the developer of health monitoring technology for NASA astronauts, this is the fitness band that tracks ECG, heart rate, steps, natural light exposure, calories, and sleep. While the device’s accelerometer tracks steps taken and distance traveled, the built-in ECG measures heart rate to more accurately calculate exercise intensity and calories burned. After sleep sensors tally the hours and quality of shut-eye, a light sensor helps improve vitality and rest by indicating underexposure to energizing natural daylight or overexposure to sleep-stunting blue rays. Data appear on the device screen or a paired mobile device running a free app. The life tracker doubles as a watch, shows incoming smartphone messages and alerts via Bluetooth, and can be worn while swimming or showering. Battery lasts a full year. Compatible with Apple iOS 7 and higher or Android OS 4.3.x and higher. Black/Titanium colored band. 9 1/2" L x 1 3/4" W x 1/2" D. (5 1/4 oz.)