Formatt Hitech 4x4" 1.5mm Resin Neutral Density Kit with 3 Filters: 1, 2, 3-stop (0.3, 0.6, 0.9) Transmission: ND 0.3: 50%ND 0.6: 25%ND 0.9: 12% Exposure: ND 0.3: +1ND 0.6: +2ND 0.9: +3 Neutral Density: 0.3, 0.6, 0.9 Filter Size: 4 x 4 inch / 101.6 x 101.6 mm