Centrifuge tubes are used to contain liquids during centrifugation, which separates the sample into its components by rapidly rotating. ExtraGene centrifuge tubes have conical bottoms, which help collect any solid or heavier parts of the sample being centrifuged. The precisely calibration, special design for providing excellent air-tightness, high transparence and low remainders, no waste of product. Choose amber or black plastics for light-sensitive samples. Clear tube with more than 99% light transparency (λ500-565nm) and black tube with less than 0.01%. Cap 50% longer ideal for avoiding contamination.