Adjustable filter for targeted reduction of light. Exposure extension between +1 and +8 (ND2-400) f-stops is possible. Rotating mount allows for individual adjustment. Coating: one layer on each side. Quality class (glass): high-quality lens glass. Allows large apertures, ideal for portraits and outdoor shots in extreme brightness, creating background blur that makes the subject stand out clearly from the foreground. Flowing water appears soft due to long exposure times, producing an impressionistic effect in cases of strong darkening.