1.78-inch 448x368 resolution LTPO OLED colour display;
Waterproof to 50 m;
32 GB internal memory;
GPS module:
Sports activity monitoring (sports modes);
Health monitoring (heart rate monitoring, sleep quality monitoring, cycle tracking app for women);
Additional features (incoming call notifications, text messages, email, calendar reminders, weather, hand wash timer, activity reminders, noise sensor);
Sensor to help detect sudden drops and send an emergency message; 
Siri and Apple Pay functionality;
A single watch should charge in up to 18 hours. (depending on usage);
Silicone strap fits 14-22 cm wrist.