This is the generic term given to the wide range of maintenance robots found aboard the typical Exterminator Super Battleship. It has been estimated that a typical ESB can have more than a thousand of such robots embarked - and they proved a capabable force to resist boarding actions by Starship Marines.
Later in the Exterminator War, armed and armoured clankers started to appear to supplment the internal defences of the ESB.

See also Close Support Robot SCA APGW Combat Robot MSS Robot