The flexible elastomer neck and plastic clip secure your phone in place, designed by Clint Spencer & Ryan Eder. Called the Vyne.
"Vyne is a hands-free viewing accessory for the smartphone. It is designed to be worn sitting down in a stationary position for viewing media content for an extended period of time. Constructed of a flexible elastomer neck and plastic clip, Vyne allows users to easily watch movies, slideshows, and video calls in a variety of configurations & locations with maximum comfort and minimum fatigue."