Ball Drones are hovering spheres approximately eight-inches in diameter that can be programmed to fly in either a specific pattern or to seek out various patterns.
Most Ball drones have a limited flight range of up to five miles and can hover for nearly an hour before they will need to recharge. Ball drones hover due to their repulser technology; a limited form of hovering that allows them to both float, change direction and fly at around twenty-miles per hour for a limited time.
Ball drones are a polite / military technology. Private citizens are not permitted to own such things but some corporates who are developing the technology have permits to explore various design flaws and sensor packages.
Most Ball Drones come equipped with thermography and video surveilance and remote sensing packages. Their metal skin allows them to enter burning or collapsed structures to look for survivors.