The Apple W3 brought Bluetooth 5.0 to the Watch inside the Apple S4 SiP and then simply stayed: five S-chip generations, both SEs, and the first Ultra all carried it, making the W3 one of the longest-serving pieces of silicon in Apple's lineup.
The W3 was the W series' quiet finale — after it, watch wireless folded anonymously into the SiPs and Apple's discrete networking ambitions re-emerged years later as the N1. Audio's branch of the family had already continued as the H series.
