This product has an oled display .42 inch .It is Bluetooth based smart watch with battery of 70 mAh and weigh 7 g. It is compatible with all the android phone with version 4.4 and above, also compatible with ios apple. I am using this from last month , it is nice .I wish I could get a big display. What I like is the caller id function which allows user to have info on watch whenever a call is arriving on phone( this works only if watch is Bluetooth connected to phone) .You can also enable app alerts , message alert via the mi fit app. There is also provision for alarm which vibrates very strong. Other functions are steps walked, distance covered and calories burned. Also it can moniter your sleep activity automatically. The mi fit app also allows to track other activities like cycling , brushing , eating etc. Overall in the price of 1.3k it offers very much features. It is nice overall product.