"Prem" is a generic product name given to Penvos Robotics Exterior Maintenance units, a type of utility android intended to carry out physically demanding tasks in environments which are hostile to human life.
This model of android is an example of combination technology: although it is mostly mechanical, with holo-based processing, it uses a bio-charger station as a source of power. It is described as being "as tall as Bruiser [is long]", which would make it about 251cm tall (almost 8'3"). A basic humanoid chassis supports a thick but flexible covering analogous to skin (→SFTD).
In 3743 ELC, one such unit accompanied a geological expedition to a planet catalogued as CC-60125-E. This was the expedition which included geologist Amarist Naeb and physical chemist Medran Morlum. Since they only had the one android, members of the expedition simply referred to their unit as 'Prem'.
When the expedition was attacked by forces unknown some time prior to March 3745, Morlum was able to alter Prem's behavioural protocols, allowing the android to injure sentient beings. From the evidence left at the expedition's base, it appears that Prem was successful in fatally wounding three attackers, all of whom were Viskr commandos. It was the discovery of these bodies by Elm Caden which would later heavily influence the weight of the Imperial Combine's military actions against the Viskr Junta (→SFTD).
On Aldava, the information broker Joarn Kages informed Caden that Prem had been with Morlum when he came to purchase codes. Prem and Morlum were both located on Woe Tantalum, where the android met its fate (→SFTD).