Band fits 140-210mm wristsCompatible with iOSBlack Sport BandGPS enabledHeart rate sensorUp to 18 hours of battery lifeWater-resistant up to 164'

Geek Squad® Certified Refurbished products are thoroughly, painstakingly and lovingly tested, so you can be sure that your device will work right, right away. Learn more about Geek Squad® Certified Refurbished products.Fundamentally redesigned and reengineered. The largest Apple Watch display yet. Built-in electrical heart sensor. New Digital Crown with haptic feedback. Low and high heart rate notifications. Fall detection and Emergency SOS. New Breathe watch faces. Automatic workout detection. New yoga and hiking workouts. Advanced features for runners, such as cadence and pace alerts. New head-to-head competitions. Activity sharing with friends. Personalized coaching. Monthly challenges and achievement awards. You can use Walkie-Talkie, make phone calls, and send messages. Listen to Apple Music¹ and Apple Podcasts. And use Siri in all-new ways. Apple Watch Series 4 lets you do it all right from your wrist.