Overview of the Urth Circular Polarizing and ND64 Lens Filter Plus+ (49mm) The Urth Circular Polarizing and ND64 Lens Filter Plus+ cuts polarized light to increase contrast and boosts color saturation and vibrancy. It also cuts 6 f-stops of light for motion blur and depth of field effects in bright light. Polarized light can wash out images with silvery reflected light and the ND64 + CPL Filter Plus+ cuts out 99.9% of reflected light from water, glass, and non-metallic surfaces, uncovering bolder colors. The ND64 + CPL also blocks a fixed 6 f-stops of light entering your camera, allowing you to use slower shutter speeds for long exposure and wider apertures for shallower depth of field effects in bright light. The Plus+ features 20-layers of nano-coating providing easier cleaning and better protection against water, oil and scratches. These layers also provide a higher maximum light transmission and a more consistent transmission curve for sharper images, finer colors and greater depth. Features of the Urth Circular Polarizing and ND64 Lens Filter Plus+ (49mm) Double-Threaded for Stacking Filters Ultra-Slim Rim Professional B270 Schott Optical Glass 1.8 (6-Stop) For more Urth Products see here.