The F5B-class was a type of Klingon Empire starship, a bird of prey created as a subclass of the Qud-class frigate in Klingon Defense Force service in the 23rd century. This Klingon bird-of-prey subclass was built on the standard QuD hull spaceframe. Ships of this type were easily modifiable, being refit and retrofit between the standard F5B and the uprated F5K-subclass. (ST video game: Starfleet Command)