Apple Watch Series 9

Series 9 used the first redesigned Apple watch processor in years. The S9 system in package contained a four-core Neural Engine that processed Siri requests directly on the wrist, so dictation and queries worked faster and without a connection.

The same chip powered Double Tap. By tapping the index finger and thumb together twice, wearers could answer calls, stop timers or scroll widgets with the hand that was wearing the watch. A second-generation Ultra Wideband chip let the watch point toward a nearby iPhone with Precision Finding.

The display became twice as bright, peaking at 2,000 nits, and could dip as low as one nit in dark rooms. In the United States, blood oxygen features were disabled shortly after launch because of a patent dispute, but the hardware remained in place.