All-day Activity Tracking: Accurately record all-day activities like steps, distance, calories burned, and active minutes Sleep Monitor: Automatically track your sleep duration and consistency with comprehensive analysis of sleep quality data; wake you up peacefully with a silent alarm Calls and Messages Reminder: Remind call, SMS and SNS notifications on your fitness tracker Built-in USB Plug: Built-in USB plug makes it easy to charge in any USB port, no cable needed. One full charge gives about 5-7 days of working time OLED Display & Replaceable Bands: See your daily activity and time on 0.86 inch OLED Display screen. 5 colors of bands gives you more choices and pleasure when replacing your band (Bands are sold separately).band length is adjustable between 5.8 inches min. and 8.5 inches max.