This is a built-in system on a great many ships that are not primarily designed for combat. The logistics benefits commonly associated with ships that happen to have this hullmod are most welcome however the sensor malus can often prove fatal in attracting pirates from quite a distance away. Mechanisms for mitigating this disadvantage can be found on the Sensors page.
Only up to date for version 0.8a-RC19. It is likely still broadly correct but not verified for the most up to date data yet. Please double check the Version History