A:Answer I don’t know anything about the 5 Series but the 4 Series works with the iPhone. As long as your phone has Apple Watch app on it, you can pair your watch to the phone. Make sure your phone has the latest software updates and you will see the app with the watch, that is what you use to pair the two. Then whichever cellular carrier you have for phone service, if you want a watch with cellular, get one that is for your carrier. You don’t have to use it with cellular but you can add it later. There is also one without cellular, in the 4, don’t know about the 5 Series.