Among the new features of the Apple Watch Series 8, Apple Watch Ultra, and the Apple Watch SE is a small GPS upgrade that went largely unnoticed until this week. And because of the change, your iPhone’s and Apple Watch’s battery last longer.

As discovered by outdoor enthusiast site DC Rainmaker, the new watches rely solely on the built-in GPS chip to track workouts and distance. It’s a notable change from the older watches, which use the GPS from a nearby iPhone to preserve battery life on the watch. Now, GPS will run solely on the Apple Watch, which means the Series 8 and SE actually have better battery life than before. Despite the new battery-draining functionality, Apple still rates battery life at 18 hours.

This change isn’t really a new revelation—it was mentioned during the Apple Watch reveal in September—but DC Rainmaker says an official Apple declaration of this change couldn’t be found until now. It was discovered in a footnote at the bottom of a support document on calibrating the Apple Watch for Workout and Activity accuracy.

The change is good news for your iPhone too–anytime iPhone battery life is preserved is a good thing. But it’s also nice to see Apple make improvements that aren’t obvious but will improve the experience of its devices. It’s also another way Apple has improved the battery life on the Watch, even if it’s not immediately noticeable. It’s similar to when the always-on display arrived with the Series 5 but still offered the same 18-hour battery life.