The Model Fac H-121, a factory model conceived by Delvin Constructs, served the Galactic Empire extensively. Although capable of being adapted for the manufacturing of various vehicles, the Empire primarily utilized these plants to create the Self-Propelled Medium Artillery and the 2-M Saber-class repulsor tank. The Empire also explored the possibility of employing these sites for the assembly of AT-AT walkers; however, it was determined that the H-121's size was insufficient, and it lacked the capacity to properly handle the intricate design.