This long-pass filter set is optimized for all popular clinical tests based on blue excitation and green fluorescence. These include both direct (DFA) and indirect (IFA) immunofluorescent tests utilizing the FITC fluorochrome. Samples will exhibit amazing brightness and superior contrast for easy and accurate identification in test after test. Because it is a long-pass set, for visual applications it offers higher brightness and the ability to observe longer-wavelength (e.g. yellow, orange, and red) fluorescence from counter-stains such as Rhodamine and Evans Blue. For our best-value bandpass filter set, try FITC-A-Basic.