SecUnits

"The practice is disgusting, it's horrible, it's slavery. This is no more of a machine than Gurathin is-" Exasperated, Overse said, "And you don't think it knows that?" (All Systems Red)

Security Units, or SecUnits for short, are bot-human constructs intended to provide security for humans and augmented humans, usually through contracts from an equipment supplier.

SecUnits are fitted with a governor module, which punishes them if their behavior deviates from a given set of programming and instructions. For example, if a SecUnit tries to sit down on human furniture, it's punished. If it hacks systems or searches for hacks without human direction, it's punished.

Augmented Rovers

According to a serial, there was a variation of SecUnit made not with cloned human tissues but with voluntary donations of matter from catastrophically damaged humans. This serial (a fictionalized documentary) portrayed these constructs as having significantly more rights in their lives than other constructs do, which Murderbot found difficult to believe.

Physiology

SecUnits do not need to consume or eliminate matter, as they are entirely battery powered. SecUnits therefore do not have a digestive system of any kind. Murderbot explains that any food or liquid consumed will end up in its lungs, which it will later need to get rid of (presumably by coughing), and it is incredibly unpleasant for it to do so.

SecUnit lungs are connected differently than human lungs, and are designed to take in much less air. Because of this, SecUnits are unable to perform rescue breathing (Network Effect, p98). SecUnits are able to survive for extended periods of time in a minimal or depleted atmosphere (e.g. in shipping containers).

SecUnits have metal framework and synthetic bones as the main supporting structure of their bodies. This is presumably very difficult to destroy, as shown by multiple near-fatal injuries to Murderbot leaving it with large pieces of missing flesh but intact bones. It's unclear which components of a SecUnit are organic vs inorganic.

SecUnits are able to dislocate joints to aid in greater flexibility with no apparent ill effects. It is also possible (albeit unpleasant) for a SecUnit to sever parts of its body at-will. This is done by uncoupling its inorganic joints. The body part may still be controllable while severed and can be re-attached.

If a SecUnit is damaged, it can go into a repair cubicle to regenerate missing tissue. SecUnits can regrow 80% of their body mass in a repair cubicle, but this does not include the organic parts of their heads.

SecUnits have no gender or sex-related bodyparts.

Physical Appearance

SecUnits have short hair and "generic human" faces. Visible bot material (such as on the head and neck) resembles that of typical augments. However, SecUnits are not designed to act or function like humans, and do not have a variety of human traits and organs. SecUnits are typically all identical in height and build, and they don't have human mannerisms or tics such as fidgeting or any sort of "tells".

SecUnits have energy weapons in a compartment on each forearm that can be used to incapacitate humans or to melt through things. These are somewhat effective on each other and can be fatal, but smaller energy weapons do little to affect SecUnits.

SecUnits don't have any organic matter on their feet.