Formatt Hitech 100x150mm (4"x6") Resin Neutral Density Grad Hard Edge 1.2 (4 Stops) for 100mm Modular holder Firecrest holder Lee 100mm System Nisi 100mm system compatible with all 100mm holder systems 4 stop (1.2) hard edge graduated ND filter Hard edge filter ideal for longer lenses Made in the UK in rugged and durable CR39 resin Compatible with Formatt Hitech 100mm , Firecrest 100mm, Lee 100mm and Nisi 100mm systems