Lee Filters SW150 Mark II Filter System Rotating Holder for Wide Angle Lenses The SW150 Mark II filter system opens up opportunities for the creative use of filters, without the need to be concerned about vignetting The SW150 Mark II filter holder comes assembled with two filter slots and includes the SW150 Light Shield The included light shield helps to prevent unwanted back reflections and creates a light tight seal enabling the use of both the Little and Big Stopper