It is essentially a giant, U-shaped magnetic coil that causes interference in the atmosphere that prevents enemy units and command interfaces from mapping or exploring a segment of the battlefield in its close proximity. A mobile version of the generator, the Mobile Gap Generator, was also produced during the Second World War.
Despite the Gap Generator's ability of creating vast patches of shroud, any Allied unit within the shroud can still be targeted by enemy units, even airstrikes.
The Gap Generator creates a persistent shroud in a radius around the structure. This shroud is temporarily lifted nearby a unit traveling through, but it returns behind the unit as it moves away. The shroud will regenerate in this manner, so long as the structure is standing and there is adequate power available.