These Costar® low binding microcentrifuge tubes feature a bonded polymer technology that reduces protein and nucleic acid binding, resulting in better sample recovery. They are made of natural (uncolored) polypropylene and are certified RNase-/DNase-free. -Supplied nonsterile and are autoclavable. -External graduations and frosted writing spot for easy sample identification. -Positive seal design allows for repeated opening and closing. -Flat cap surface for convenient labeling. -Withstands a maximum RCF of 17,000xg