Apple Watch Series 4

The Apple Watch Series 4 was a line of 4th generation smartwatches designed and produced by Apple Inc. The watch was released on September 21, 2018, along with the iPhone XS and iPhone XR at Apple's annual September event in the Steve Jobs Theater. It succeeded the Apple Watch Series 3.

Features
The Series 4 was the first Apple Watch to come in two new sizes: a 40mm and a 44mm case size, superseding the 38mm and 42mm case and matching band sizes of the past. Cases were also available in stainless steel.

Nike+
A special edition Nike+ version of the Series 5 was made with added benefits such as a map of your run, special custom watch faces, some that represent various Nike products, the Nike+ Run Culb app built-in, and exclusive Nike bands.