The Apple Watch Series 5 was first introduced at Apple's "By Innovation Only" keynote on 10 September 2019. Internally, the Apple Watch Series 5 is referred to as N144sAP (Watch5,1 - 40mm), N144bAP (Watch5,2 - 44mm), N146sAP (Watch5,3 - 40mm Cellular) or N146bAP (Watch5,4 - 44mm Cellular).
The Apple Watch Series 5 uses the same T8006 CPU as the Apple Watch Series 4, except it adds a built-in magnetometer
and it was rebranded as the "Apple S5".
It also contains a GPS module, and on cellular models an LTE chip.
- https://www.apple.com/apple-watch-series-5 Archived 2019-09-23 at the Wayback Machine