Apple's employees who participated in the company's annual Close Your Rings Challenge have begun to receive a limited-edition Apple Watch band and a special enamel pin marking the 10th anniversary of the internal challenge.

This year's band is a black Sport Loop with special lugs and an end piece that are colored similarly to the Apple Watch's Move, Exercise, and Stand rings.

Given that these bands are limited to Apple's employees, rather than being sold directly to customers, they are relatively rare. You can keep track of hundreds of Apple Watch bands released since 2015 through the Bandbreite app on the iPhone.