i7 tracks real-time heart rate while exercising by displaying on the screen directly. i7 provides various vibration remind during fast and intense movement,which helps people more effiency and personalization to understand their heart rate zone. To achieve high-effect of exercise, i7 also supports 24 kinds of sport management to check the intensity and calories burned of exercise.by summarising the distance,duration,step frequent, pace and others data under the running mode is especially design for runner. better dispalying in the sunlight by use the lower-power comsumption Memory LCDP and Backlight Design to reduce eyes harm.We fully concern about the outdoor enviornment,the more brightness, the more plays the best performance. up to 7 days battery life under the real-time heart rate mode.alternatively,using as normal mode will takes up to 30 days. 2.5D Tempered Glassed,Anti-scratch & Abrasion Resistant.Inspired by the water looks Crystal mellow when flows in the form of a plane .i7 adopt All-Metal body to improve handle, and protect the chips.Using medical grade of wrist strap to prevent the allergy,also can be changed at will as long as the size of 20mm wrist strap.