Formatt Hitech Limited HT100ND3.0 100 x 100MM (4 x 4-Inch) Neutral Density 3.0 Filter NDs are made in different densities according to the level of light reduction from 1/3 to as much as 10 Stops of light. The 3.0 ND reduces light by 10 Stops. Hitech filters are made from the highest quality 1.5mm optical resin.