Audio Sharing allows pairing two sets of headphones to the same iPhone or iPod, so you and another person can listen to the same tune or watch a movie together. It requires an iPhone 8 or above, and is activated through the Bluetooth menu in Settings.
Before, the feature was available on AirPods and Powerbeats Pro, but it will soon come to all Beats headphone models that use Apple H1 and W1 chips. That includes the Studio3 Wireless, BeatsX, Powerbeats3 Wireless and Solo3 Wireless models as well as the Powerbeats Pros.
The feature will be available on Beats headphones from September 23rd.