From Apple Newsroom:
Apple’s second-generation Ultra Wideband chip — the same chip found in the iPhone 17 lineup, iPhone Air, Apple Watch Ultra 3, and Apple Watch Series 11 — powers the new AirTag, making it easier to locate than ever before. Using haptic, visual, and audio feedback, Precision Finding guides users to their lost items from up to 50 percent farther away than the previous generation.
Solid update – nothing especially new, just better.