B+W 55mm MASTER Neutral Density 803M (25%, 3 stop) Filter, darkens the subject area by three f-stops without changing its color. Ideal for Landscape Photography, the 803M is finely polished glass and lasts longer than easily scratchable plastic substrates. It is used when no suitable aperture can be selected in bright light or when a specific, short DOF is required. With this filter, distinct flow of water effect becomes apparent, and it also is good for shooting photos with a wipe effect.