This amazing fitness watch has an astounding 20 days standby time. Low power consumption, long standby, one charge can last up to 7 days of usage. Vibrates when receiving a call or message. 
 
Features and Specifications:

Compatibility: All Compatible
Style: Sport
Touch Screen: Yes
Functions: Fitness Watch, Message Reminder, Call Reminder, Calendar, Passometer, Alarm Clock, Remote Control, Sleep Tracker (recording your sleep state), Heart Rate Tracker, Push Message, Social Media Notifications, Sports Monitoring, Sedentary Reminder, Distance (Step Tracker), Blood Pressure Reader, Remote Control Picture, Find The Phone, Durable, Back Clamping Charge
Application Age Group: Adult
Band Material: Silica
Language: English
Waterproof Grade: Life Waterproof
Brand Name: Robotsky
Screen Style: Rectangle/Square-shape
Screen Type: LED
Model: V66 Smart Bracelet
Display: 0.66 inch OLED
Battery: 80 mAh
Standby time: About 15 days
System support: Android system version 4.4 and above, iOS system version  8.0 and above
Bluetooth: BLE 4.0 or above
Working time: Approx. 7 days
APP/APK download: FitCloud
Colour: Black, White and Pink
Product size: Approx. 48*24.3*12mm