Firecrest ND 100x100mm (4"x4") Neutral Density 4.8 (16 Stops) long exposure filter for Firecrest 100mm holder, Formatt Hitech 100mm Modular Holder, Lee 100mm System, Nisi 100mm System 100mm filter reduces light by 16 F-stops Firecrest technology is neutral across the whole spectrum, including UV, visible and infra red Firecrest coating is sandwiched within filter, providing protection against scratching and damage Made in the UK using Schott Superwite glass, the finest optical glass available Compatible with all 67mm holders, so a single filter can be used on multiple lenses