The Apple Watch Series 12 and Ultra 4, now in stores since September 18, bring the new Health Sensing System and S11 chip for higher-frequency heart rate and HRV readings plus a Readiness score. Series 12 reaches up to 24 hours of everyday battery life with 15-minute charges adding 12 hours; Ultra 4 stretches to 50 hours. Ceramic options return alongside aluminum and titanium finishes. These are confirmed official features from the September event, not pre-announcement leaks.