This is an Eggcrate for the Mole-Richardson 4000W Super-Softlite.

Eggcrates are essential accessories for any lighting system. An eggcrate alters the shape and intensity of the light output from your light fixture. Consider an eggcrate as a painter would a brush or a sculptor would a knife or chisel.

An eggcrate is a rigid or semi-rigid plastic or metal grid that narrows the spread of light. The spread of light will be determined by the density of the honeycomb mesh, and the distance of the subject from the light. Unless specified otherwise, an eggcrate mounted on a light fixture will limit the spread of light to about 40° from the face of the fixture.