The Soft Set from Lee consists of five filters, each offering a subtly different degree of diffusion for use in portraiture and landscape photography. The soft effect is virtually independent of any aperture or focal length variations. This set also contains the Lee Gel Snap. The Gel Snap is Lee's easy and affordable filter holder. Simply insert your 4 x 4" filter, snap it shut, and "snap" it on to any lens 82mm or smaller using the included "Elastomeric Tension Device", also known as an "E.T.D.", i.e, rubber band.