The T-21 light repeating blaster, alternatively referred to as the T-21A, T-21 heavy blaster, or simply the T-21 blaster rifle, represented a light repeating blaster model produced by BlasTech Industries. Initially employed by the Grand Army of the Republic during the Clone Wars, with a documented instance of at least two clone troopers utilizing T-21s during the First Battle of Geonosis in 22 BBY, it later saw service within the Galactic Empire's Stormtrooper Corps. This weapon provided rapid fire and accuracy at extended distances, though its capacity was limited to only 30 shots, thus limiting its suppressive fire capabilities; however, this limitation could be overcome by connecting it to a generator for continuous firing.
The design of the T-21 was partially influenced by the DC-15A blaster rifle utilized by clone troopers of the Galactic Republic. It is known that both Magma troopers and shadow troopers made use of the T-21. Leading up to the Battle of Yavin, some of the stormtroopers sent to the planet Tatooine in pursuit of stolen Death Star plans were equipped with T-21s. The T-21B heavy blaster, a marksman variant featuring optics, was derived from the T-21's design.