Jem'Hadar Attack Vessel 971 was a Jem'Hadar starship that was in service in the 24th century.
In 2376, Odo selected Jem'Hadar Attack Vessel 971 for his mission to locate the Progenitor. Odo did so due to his familiarity with the crew. (DS9 - Worlds of Star Trek: Deep Space Nine novel: The Dominion: Olympus Descending)
In 2383, Odo and the crew of Jem'Hadar Attack Vessel 971 attempted to warn Starfleet that rogue elements of the Typhon Pact had stolen Dominion technology. (ST - Typhon Pact novel: Raise the Dawn)