The ZH-28 guard was a security droid design produced by Stonewall Labs during the Imperial Period. This particular droid model possessed a humanoid form and stood at a height comparable to an average Human. The ZH-28 guard was equipped for combat and utilized ranged weaponry.
Stonewall Labs produced the ZH-28 guards before the Battle of Yavin took place. When the Stonewall Labs installation on Naboo was shut down, the security droids were left in an active state. A collection of ZH-28 guards, alongside SWL-5 overseers, LC-92 antagonists, Mechthorians and B1-series battle droids, continued their assigned patrol routes within the laboratory complex and its surrounding territories. In 1 ABY, a spacer sought to obtain an experimental Old Republic droid component from a droideka located inside the Stonewall Labs facility. The spacer infiltrated the laboratory and engaged in combat with several ZH-28 guards in order to ultimately secure the module.
The ZH-28 guards made their debut appearance in the 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game that was developed by Sony Online Entertainment and published by LucasArts, before the game's servers were shut down on December 15, 2011. The ZH-28 guards were integrated into the game as a component of the "Legacy Quest" content update, which was released alongside "Publish 25," also referred to as the "New Game Enhancements," on November 15, 2005.
They shared a common design model with both the CY-M Prototypes and the Chirq Council Mechanized Guardians.