NEST centrifuge tubes are made of high-clarity polypropylene. The thickness of tube wall is more uniform and can sustain 12,000g. The caps are designed by a German institute to make them have 2 leak proof design and easier to screw. The tubes are designed for maximum allowable temperature of 120⁰C and minimum allowable freeze temperature to -80⁰C. The silk printing won't fade nor be scraped after autoclaved. All tubes are steriled with gamma irradiation and non-pyrogenic.