https://techcrunch.com/2023/09/12/apple-watch-ultra-2-arrives-with-new-s9-chip/

In addition to the new Series 9,  the company morning announced an update to last year’s Apple Watch Ultra. The Apple Watch Ultra Series 2 is powered by the S9 chip — same as the Series. The crowd at today’s event let out an audible gasp when the company revealed that the rugged smartwatch has a peak brightness of 3,000 nits.

The company still managed to keep the Ultra 1’s battery with 36 hours on a charge or 72 with Low Power Mode