It tells you what your heart rate and blood pressure. You will have to charge it for a half an hour and it tells you with-in a minute. It’s like a fitbit, but better because it tells you if you are good or bad health. The device is to work in the sunlight and the working part is ABS plastic with solar light paper on top to charge the device and make it work, but it can only work in the sun light and no other light. The bracelet is flexible plastic with a clip that is steel. This device is very useful when ur looking around on the planet. The device can be out in any kind of air like gas. Mars is a good planet to use the device on because it is the fourth planet from the sun and it is 195 degrees F. This device can be in any weather or and any temperature. The device can be in the water, but it has to stay in the sunlight whatever you do or where ever you are in space. The bracelet can fit any wrist and it be replaced at anytime in the time you want.