An Auspex, also called a Multi-scanner, or simply a Scanner, is a short-ranged Imperial sensor device used to detect motion, invisible gases and energy emissions across a wide band of the electromagnetic spectrum. This includes such emissions as heat, radiation and most forms of energy given off by vehicles and living troops. Their main tactical use is to use the Auspex to triangulate the location of otherwise hidden enemy forces and allow them to be fired on by Imperial troops. The standard range of an Auspex is fifty metres, although walls more than fifty metres thick as well as certain types of building materials are able to block their active and passive sensor modes. An Auspex can take the form of a separate hand-held device, or its mechanism may be built into a helmet such as in the case of the Adeptus Astartes.