D21 Watch4 Smartwatch – 1.52" Bluetooth Calling, Heart Rate & SpO2 Monitor, Wireless Charging, 10m Range (Android Compatible)​

"Bigger Screen, Smarter Health Guardian"​​ A health-focused smartwatch that keeps your family connected and protected. ​​Key Features​​ ​​Bluetooth Calls Anywhere​​ – Stable connection up to 10m from your phone. ​​Medical-Grade Sensors​​ – Tracks heart rate & SpO2 during sleep/workouts. ​​Wireless Charging​​ – 2-hour full charge, lasts 5 days typical use. ​​Swim-Ready​​ – IP68 rating withstands pool laps and heavy rain. ​​Family Safety​​ – Emergency SOS vibration alerts for elderly users. ​​Life-Changing Moments​​ ​​For Runners​​ – "Heart rate alerts saved me from overtraining twice!" ​​Sleep Tracker​​ – "Discovered my SpO2 drops at 3AM – doctor confirmed mild apnea." ​​Commuter Hack​​ – "Answered client calls while my phone stayed buried in my backpack." ​​Pro Tips​​ • ​​Battery Extender​​ – Turn off Bluetooth at night for 7-day endurance. • ​​SOS Setup​​ – Hold side button 3sec to notify emergency contacts. • ​​Data Export​​ – Sync health reports to Google Fit via companion app.