The black delta-shaped badge worn by operatives of Section 31 in the 2250s, which also works as a communicator activated by touch, before such devices were standard in Starfleet.
In the era of Star Trek: Discovery, Starfleet's secretive intelligence division marks its people with an all-black version of the service insignia. Officers wearing black badges are seen aboard Discovery in the first season, before their meaning is explained.
The badge is identified in the second season. Ash Tyler joins Section 31 under Leland after the events of Point of Light and carries one when he is posted to Discovery. Unlike the ordinary insignia of the time, it contains a communicator that can be operated with a tap, anticipating the combadges of the following century.
The badges are seen throughout the season on Leland, Philippa Georgiou and other agents during the search for the Red Angel and the fight against Control.