AMAZON ALEXA BUILT-IN: Talk to Amazon Alexa on your Amazfit Band 5 activity fitness tracker. Ask Alexa questions, get translations, set alarms and timers, check the weather, control your smart home devices, and more..Water resistance depth:50 meters. 15-DAY BATTERY LIFE: Say goodbye to daily recharge. With a fully charged Amazfit Band 5, you don’t need to bring a charger for a two-week trip. On a single charge, it has enough power to get you charged for 2 whole weeks mind-free. BLOOD OXYGEN SATURATION MONITOR: You can measure your blood oxygen saturation and understand your physical state with OxygenBeatsTM. Ideal for high-intensity workouts and sports such as marathons and gym workouts. 24/7 HEART RATE, SLEEP TRACKER: With Huami-proprietary BioTracker TM2 PPG optical sensor, this health tracker performs 24/7 real-time heart rate monitoring and high heart rate warning. Band 5 can also professionally interpret the sleep characteristics at each stage and analyzes sleep quality, to help you adjust your sleep habits. It even monitors your 20-minute daily nap. YOUR SMART SPORTS COMPANSION: An ultimate easy-to-use activity fitness tracker with 11 built-in sports modes, enable you to record the distance, speed, heart rate changes, calories burned, and other data during your workouts. With a water-resistance grade of 5 ATM, Band 5 can withstand all your daily activities and you can wear it while swimming. WOMEN’S HEALTH TRACKING: With the female period tracking system, Band 5 records and predicts the female menstrual cycle and sends smart notifications reminders.