This series features Chroma’s Modified Magnetron sputter coatings (ET) which achieve the highest transmission levels for interference filters. Like the 41000 series, these filters also have a very steep transition from peak transmission to high optical density to best exploit the spectral properties of modern fluorochromes with short Stokes shifts. These filters offer the greatest hardness and durability against environmental factors such as high heat and humidity, and will last much longer than soft-coatings. Additionally, use of our ET filters assures image registration between filter sets in imaging systems which are otherwise in perfect register.