The Lee 21 X 24 Inch Sheet Leelux Diffusion Gel Filter 400 is a dense white diffuser used for wide beam spreads; creates an even, soft, field of light without shadows. Manufactured on a 125 micron polyester base. A range of solutions for softening and spreading a light beam and reducing the contrast ratio between highlight areas. The range includes polyester diffusion filters, frosts, flexi-frosts, perforated diffusions, grid cloths and spun materials all in different densities for a wide range of lighting effects.