Firecrest ND 49mm Neutral density ND 0.9 (3 Stops) Filter for photo, video, broadcast and cinema production Firecrest technology is neutral across the whole spectrum, including UV, visible and infra red 49mm diameter stackable filter reduces light by 3 F-stops Firecrest multicoating technology makes the filter hydrophobic and scratch resistant Manufactured in the UK using Schott Superwite glass, the finest optical glass available