Level 6 planet
From Tardis Wiki, the free Doctor Who reference
A Level 6 planet was a designation used by Galactic Law in reference to certain worlds, specifically their technological development. Other known designations include Levels 1, 2, 4, and 5.
Level 6 planets had the technology capable to create sonic devices, such as sonic screwdrivers. (PROSE: Ghosts of India)
