This is a 40° fabric grid for the Profoto 1 x 4' softbox.
Grids are essential accessories for any lighting system. A grid alters the shape and intensity of the light output from your softbox when it is mounted on a light head. Consider a grid as a painter would a brush, or a sculptor would a knife, or chisel.
Honeycomb grids and "egg crates" are rigid, or semi-rigid. Fabric grids are hand-stitched, and collapse easily for storage or transport. Use of a fabric grid, honeycomb grid, or "egg crate" will result in a narrower 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, a grid mounted on a softbox will limit the spread of light to 40° from the face of the softbox.