The PreSafeStained 100bp DNA Ladder contains 8  DNA fragments ranging from 100bp to 3Kb. It is pre-stained so it can be visualized directly after running the gel without further DNA staining steps. The SafeStain 6X DNA Loading Dye contains two tracking dyes and also the same safe green fluorescent dye as in DNA ladder. The two tracking dyes are for monitoring the running of the agarose gel, and the green fluorescent dye is to stain the DNA samples. By using this special DNA loading dye, your agarose gel will reveal two different colors, blue and yellow while running and green fluorescent bands of DNA under LED or UV light without extra staining steps. DNA ladder and your samples will emit a green light (530nm).