The Blue solid color effects filter creates a realistic cooling blue effect. It is available in 3 densities, 1,2 and 3. Different color filters can be used in combination together or with graduated color or neutral density filters to create interesting bespoke effects. This 100mm filter is usable with Hi-tech 100mm holder systems or any 100mm (4-Inch) holder. The filter is also available in 85mm, 150mm and 165mm sizes. Hi-tech filters are made from the highest quality 1.5mm optical resin.