Haida PRO II Multi-Coated Square ND 3.6 4000X 12 Stops Optical Glass Neutral Density Filter, 150x150mm High quality optical glass. Multi-Coated ND4000 / ND3.6 / 4000X / 12 F Stops 150mm x 150mm Includes 2 x Self Adhesive Foam Gaskets & Metal Tin / Case