Fitting their purpose, Mark IV droids were equipped with an extensive sensor complement in place of traditional weaponry. The droid featured electromagnetic, infrared, and visible-light sensors, in addition to three hours worth of holorecording memory. They were capable of flying up to 15 meters in the air via built-in repulsorlifts.
Because of their powerful sensory equipment, Mark IV droids were used for a variety of tasks: battlefield reconnaissance, surveying, and sentry and patrol duties. The droids were even capable of long-range surveillance due to the inclusion of a holorecording rig. Although equipped with basic personality programming and self-preservation instincts, Mark IV droids were compelled to obey orders given to them, leading cautious commanders to scout dangerous terrain ahead with the essentially expendable droids.
Hundreds of Mark IV droids were deployed from the Devastator during the Galactic Civil War to scout the planet of Tatooine, where they searched the crowded streets of Mos Eisley in cooperation with sandtroopers searching for C-3PO and R2-D2.
One such droid interrupted an ASP-series droid assembling what it thought to be an illegal antenna. The ASP droid responded by smashing the Mark IV.
- "The Secret of Tet-Ami"—Star Wars Tales 13
- Star Wars: Episode IV A New Hope (First appearance) (Special Edition and DVD releases)
- Star Wars Episode IV: A New Hope junior novel
- Star Wars Galaxies: An Empire Divided
- Star Wars: Jedi Knight: Dark Forces II
- Star Wars: Jedi Knight: Mysteries of the Sith
- "Bridge to the Universe: Digital Technology and the Making of The Star Wars Trilogy Special Edition"—Star Wars Insider 32 (as Probe droid)
- Star Wars Trilogy Sourcebook, Special Edition (as Mark IV Patrol Droid)
- Star Wars Customizable Card Game – Special Edition Limited (Card: IM4-099)
- (Picture & text only)
- Coruscant and the Core Worlds
- The New Essential Guide to Droids
- The Official Star Wars Fact File 3 (SEN1-2, Imperial Mark IV Sentry Droid)
- The Official Star Wars Fact File 10 (HUN1, The Hunt for the Droids)
- Inside the Worlds of Star Wars Trilogy
- Star Wars: The Complete Visual Dictionary
- Threats of the Galaxy
- The Complete Star Wars Encyclopedia (As "Mark IV patrol droid")