The barndoors, Snoots, Grids, and Filters are essential accessories for any lighting system; these devices change the shape, intensity, or color of the light output from your flash heads. Use of a barndoor set will result in a shaft of light, when attached to the reflector of light source. The size of the shaft of light will be determined by the opening of the leaves, and the distance of the light from the subject. Rotating the barndoor set will determine the angle of the shaft of light.