http://www.techradar.com/news/best-smartwatch-for-iphone-what-great-watches-work-with-your-iphone

Things have moved quickly in the smartwatch space since the release of the original Apple Watch in 2015. We've already had an updated version called the Apple Watch 2 and that's already been discarded in favor of the newly-announced Apple Watch 3.

On top of that, there's now a plethora of other smartwatches you can use with your iPhone.